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HAND-BOOK 



ANATOMY. 



HAND-BOOK 

OP 

ANATOMY: 

Wity (to Imitoi unit /iffy-Jim? Sllnstrntinnjg, 



BEING A PORTION OF 



AN ANALYTICAL COMPENDIUM 



VARIOUS BRANCHES OF MEDICINE. 



john'neill, m. d., 

SURGEON TO WILLS' HOSPITAL, DEMONSTRATOR OF ANATOMY IN THE UNIVERSITY OF 

PENNSYLVANIA, LECTURER ON ANATOMY IN THE PHILADELPHIA MEDICAL 

INSTITUTE, FELLOW OF THE COLLEGE OF PHYSICIANS, ETC., 

AND 

FRANCIS GURNEY .SMITH, M.D., 

LECTURER ON PHYSIOLOGY IN THE PHILADELPHIA ASSOCIATION FOR MEDICAL INSTRUCTION, 
PHYSICIAN TO THE ST. JOSEPH'S HOSPITAL, ETC. 



SECOND EDITION, REVISED AND IMPROVED. 








PHILADELPHIA: 

BLANCHARD AND LEA. 

-1852. 



ft 






U. SHEEMAX, PRINTER. 



CONTENTS. 



PAGE 

Definition of Anatomy, - - - - - - -13 

SECTION I. 



General anatomy of bone, ------ 14 

Periosteum, --------14 

Marrow, --------15 

Formation and growth of bone, - - - - 15 

Callus, ________ 15 

Cervical vertebrse, - - - - - - -16 

Dorsal vertebrse, - - - - - - - 17 

Lumbar vertebras, - - - - - - -17 

Sacrum, --------18 

Coccyx, _____-._ 18 

Innominatum, - - - - - - - 19 

Sternum, -------- 21 

Ribs, 22 

Bones of the cranium, - - - - - 23 

Bones of the face, -------30 

Hyoid bone, - -. - - - - - 36 

Scapula, - - - - - _._ _ 37 

Clavicle, - - - - - - - 38 

Humerus, --------38 

Ulna, --------- 39 

Radius, -------- 40 

Carpus, - - -.- - - - -41 

Metacarpus, __._.__ 42 

Phalanges of the fingers, - - - - - 42 

Femur, ------ .: _ 43 

Patella, - - - 44 

Tibia, ----.._. 44 

Fibula, - - - -• - - - 46 

Tarsus, -------- 46 

Metatarsus, ------'.-- 48 

Phalanges of the toes, ------ 49 



VI CONTENTS. 

SECTION II. 

ARTICULATION S. 

PAGB 

Of ligaments generally, - - - - - - 49 

Ligaments of the lower jaw, - - - - - - 51 

Ligaments of the vertebrae, ----- 52 

Ligaments of the pelvis, - - - - - 53 

Ligaments of the ribs, ------ 54 

Ligaments of the shoulder, - - - - - 55 

Ligaments of the elbow, ------ 57 

Ligaments of the wrist, - - - - - 58 

Ligaments of the fingers ------ 58 

Ligaments of the hip. - - - - - - -59 

Ligaments of the knee, ------ 59 

Ligaments of the ankle, - - - - - - 60 

Teeth, -------- 62 

Cellular tissue, --------64 

Fat, -------- 65 

Skin, - - 65 

Nails, -------- 66 

Hair, --------- 67 

SECTION III. 

MUSCLES. 

General anatomy of, ------ 69 

Muscles of the head and face, - - - - - 70 

Muscles of the neck, ______ 72 

Muscles of the chest, - - - - - - -74 

Muscles of the abdomen, ------ 76 

Anatomy of Inguinal Hernia, - - - - - - 77 

Muscles of the back, ___..__ 83 

Muscles of the shoulder and arm, - - - - - 86 

Muscles of the forearm, ------ 87 

Muscles of the hand, -------90 

Anatomy of femoral hernia, ----- 92 

Muscles of hip and thigh, - - - - - - 94 

Muscles of the leg, _-___- 96 

Muscles of the foot, - - - - - - -98 

SECTION IV. 

VISCEBA. 

Mouth, -------- 100 

Tongue, -------- 100 

Muscles of tongue, ------- 101 

Palate, - - - - - - - - - - 102 

Salivary glands of the mouth, - - - - - 103 

Pharynx and oesophagus, - - - - - -104 



CONTENTS. Vll 



^ PAGE 

Regions of abdomen, ______ 106 

Peritoneum, - - ______ 107 

Mesentery, -------- 108 

Stomach, - - - - - - - 109 

Intestines, -------- 111 

Liver, --------- 116 

Gallbladder, ------- 119 

Pancreas, -------- 119 

Spleen, -------- 120 

Kidneys, - - - - - - - - 121 

Supra-renal capsules, ------ 122 

Bladder, - 122 

Penis, -------- 123 

Vesiculoe seminales, ------- 126 

Prostate gland, ------- 126 

Scrotum and testicles, ------- 126 

Spermatic cord, ------- 128 

Muscles of perineum and anus, -___..._ 130 

Larynx, - - - - - - ■ - - 131 

Trachea, - - - - - - - - 134 

Thyroid gland, - - - - - - 135 

Lungs, --------- 135 

Pleura, -------- 136 

Mediastinum, - - - - - - - -137 

Thymus gland, ------- 137 

Heart, - - - - - - - - 137 

Pericardium, --___-_ 137 



SECTION V. 



VESSELS. 



Structure of arteries, - - - - - - -140 

Aorta, -------- 140 

External carotid artery, ______ 141 

Internal maxillary artery, ------ 142 

Arteries of the brain, ------- 143 

Subclavian artery, - - - - - - - 144 

Axillary artery, - - - - - - -145 

Brachial artery, ------- 146 

Thoracic aorta, ------- 147 

Abdominal aorta, ------- 148 

Cceliac axis, -------- 148 

Superior mesenteric artery, ----- 149 

Renal artery, -------- 150 

Inferior mesenteric artery, - - - - - 150 

Internal iliac artery, - - - - - - -151 

External iliac artery, - - - - - -153 

Femoral, -------- 153 

Anterior and posterior tibial, ----- 154 

Veins, --------- 156 

Veins of the head and neck, _____ 156 

Sinuses of the dura mater, - - - - - -157 

Veins of the upper extremity, - - - - - 159 



Y]il CONTENTS. 

PA.G3 

Ascending cava, _____-- 160 

Descending cava, ------- 160 

Yena azygos, -------- 161 

Portal vein, ____--_ 161 

Teins of the lower extremity, - - - - - -162 

Lymphatics, ___-_-_ 162 

SECTION VI. 

NERVOUS SYSTEM. 

General anatomy of, - - - - - - 163 

Membranes of the spinal marrow, - - - 163 

Spinal marrow, - - - - - - -164 

Membranes of the brain, - _ _ _ _ _ 165 

Brain, --------- 166 

Cranial nerves, - - - - - - - - 169 

Spinal nerves, - - - - - - - -174 

Cervical nerves, - - - - -* - 175 

Dorsal nerves, -------- 176 

Lumbar nerves, - - - - - - -176 

Sacral nerves, -------- 177 

Sympathetic nerve, ------ 179 

Cervical ganglia, - - - - - - -180 

Thoracic ganglia, ------- 181 

Lumbar and sacral ganglia, ------ 182 

SECTION VII. 

ORGANS OF SENSE. 

Nose, 1S2 

Eve and its appendages, ___-_- 183 

Ear, - - - - - - - - 187 



ANATOMY. 



Anatomy is the science which investigates the structure and 
organization of living beings. 

Special Anatomy or Descriptive Anatomy is the consideration of 
each organ or part of the human body, including its size, weight, 
colour, shape, &c. 

General Anatomy investigates the different tissues or structures 
out of which organs are formed. 

Surgical Anatomy or Regional Anatomy is the study of the re- 
lation of one part to another, and is one of the most important 
applications of anatomy to the practice of medicine and surgery. 

Physiological Anatomy considers the uses and functions of organs 
in a healthy state. 

Pathological Anatomy regards the different organs altered by 
disease. 

This is a compendium principally of special anatomy ; and is 
divided into seven sections : 

1. Bones. 

2. Ligaments. 

3. Muscles. 

4. Viscera. 

5. Vessels. 

6. Nerves. 

7. Special Senses. 



14 



SECTION I. 
BONES. 

GENERAL CONSIDERATIONS OF BONE. 

The bones of the skeleton are two hundred and eleven in number, 
of which twenty-two belong to the head, fifty-six to the trunk, sixty- 
nine to the superior and sixty-four to the inferior extremity ; when 
held together by ligaments and cartilages they form a natural 
skeleton, when by other means an artificial skeleton. They are 
hard, white, and inflexible ; and more numerous in childhood than 
in old age. 

They are classified into long, thick, and flat bones. The body or 
shaft of a long bone is called Diaphysis ; its articulating extremities, 
Epiphyses j its processes and projections are called Apophyses. The 
small foramina on the surface of bones are for the transmission of 
nutritious vessels, the largest of which enters about the middle. 

Bones are composed of two structures, compact and cellular. The 
compact structure consists of small fibres arranged in laminas ; each 
of these fibres has a canal running through its length, called the 
canal of Havers, transmitting vessels ; it communicates with small 
lenticular excavations, called corpuscles of Purhinje, by radiating 
tubes. The cellular structure increases the volume and strength 
without increasing the weight, and also diminishes the effect of con- 
cussion. The cells communicate with each other, and contain 
marrow. 

Composition of Bones. — Bones are chemically composed of ani- 
mal and earthy matters, united in the proportion of two parts of 
earthy to one of animal. By the analysis of Berzelius, they consist 
of thirty-two parts of gelatine, one part of insoluble animal matter, 
fifty-one parts of phosphate of lime, eleven of carbonate of lime, two 
of fluate of lime, one of phosphate of magnesia, and one of soda and 
muriate of soda. The earthy matter is most abundant in bones of 
the cranium : the animal matter in the cellular structure. Com- 
bustion will remove the animal matter, and dilute acids will remove 
the earthy matter. 

The Periosteum is a white fibrous membrane investing the exter- 
nal surface, adhering less firmly in infancy, and becoming ossified 
in old age. It is vascular, insensible in health, assists in the 
secretion of the external laminae, restrains ossification within proper 



BONES OP THE TRUNK. 15 

limits, receives the insertion of muscles, tendons, &c. and protects 
the bone from suppuration in the vicinity. 

Marrow is contained in a fine vascular membrane, lining the me- 
dullary canals and cells of bones, called the Internal Periosteum. 
It resembles fat, but consists of finer granules ; in consumption, 
dropsy, &c, it is absorbed and its place is supplied with serum. 

Formation and growth of bones. — There are three stages of ossifi- 
cation in the embryo. The first is the mucous or pulpy, which 
continues for one month ; the second is the cartilaginous, and the 
third the osseous, commencing at the third month. The colour of 
the cartilage deepens and then a vessel conveys red blood to a cen- 
tral point, which first receives calcareous particles and is called 
punctum ossificationis. Bones increase in length by continued 
deposit at their extremities between the Diaphysis and the Epiphy- 
ses, as is proved by Hunter's experiment of placing two shot in the 
tibia of a young pig ; after the animal had reached full size, the 
shot were found at their original distance from each other. Bones 
increase in thickness by external deposit and by secretion from the 
periosteum, which is proved by disease and the experiment of feed- 
ing a young pig with food coloured with madder. Yarious laminae 
of white and coloured bone can be produced by suspending and 
resuming this mode of feeding. While deposit is taking place upon 
the surface of a bone, absorption is going on internally ; this is 
proved by Duhamel's experiment of surrounding a long bone of a 
young animal with a metallic ring; after the animal was fully 
grown, the ring was found in the medullary canal, which increases 
in size by this constant deposit and absorption. 

Callus. — When bones are fractured, the process of reparation 
resembles that of the formation of a bone. Blood is effused, and 
lymph is thrown out, causing a swelling. Afterwards the blood is 
absorbed and the lymph becoming cartilage ossifies in the form 
of a ring, which surrounds the seat of fracture, and also in the 
form of a pin in the medullary canal. 

After the fractured extremities have united, the superfluous ring 
and pin of bone which acted as splints are absorbed. Whilst this 
process is going on, it is important that the parts should be main- 
tained at rest, otherwise the process of ossification is arrested, and 
a false joint results. 

BONES OF THE TRUNK. 
The trunk consists of the Spine, Pelvis, and Thorax. 

SPINE. 

It extends from the head to the coccyx at the posterior 
part of the trunk, having several curvatures. In the neck ifc is 



10 BONES OF THE TRUNK. 

convex anteriorly, in the thorax concave, in the loins convex, and 
in the pelvis concave. It contains an osseous canal for the spinal 
marrow, and is formed of 28 or 29 separate bones, called vertebrae, 
24 of which are classified as true vertebrae, on account of their mo- 
bility, and the 5 remaining are called false vertebrae. The true 
vertebras are divided into 7 cervical, 12 dorsal, and 5 lumbar ; the 
false vertebras consist of the sacrum, and 3 or 4 coccygeal bones. 

A vertebra consists of a body, 7 processes, and a spinal foramen. 
The body is in front, and is the thickest part ; it supper and lower 
surfaces articulate with a contiguous vertebra by means of a carti- 
lage ; it is convex anteriorly from side to side. The processes are, 
one spinous, of a triangular shape, and situated behind for the at- 
tachment of muscles; two transverse, one projecting horizontally on 
either side for the attachment of muscles and ligaments ; and four 
cblique processes, two of which are superior and two inferior, which 
are for the purpose of articulation. The spinal foramen is in the 
middle, and constitutes a portion of the spinal canal. The inter- 
vertebral foramen is formed on each side by a groove upon the 
upper and lower surface of each vertebra, and transmits a spinal 
nerve. 

CERVICAL VERTEBRA. 

Fig. 1. The bodies are small, and flattened 

in front; the superior surfaces 1 are 
concave laterally, the inferior are con- 
cave antero-posteriorly; they gradually 
increase in size. The spinous pro- 
cesses* are short, thick, horizontal, and 
bifid. The oblique processes are flat, 
oval, and short ; the superior 7 look up- 
wards and backwards, and the inferior 3 
downwards and forwards at an angle 
of forty-five degrees. The transverse 
processes 5 are broad, perforated at their base by a foramen 6 for the 
transmission of the vertebral artery. The spinal foramen 2 is very 
large and triangular. 

The first cervical vertebra is called the atlas ; it has no body, 
and resembles a ring. In place of a body, there is an arch which 
has a tubercle in the middle of its anterior surface ; in the corre- 
sponding part of its posterior surface is an articular fossa for the 
processus dentatus of the second vertebra. The posterior arch has a 
tubercle instead of the spinous process. The superior oblique pro- 
cesses are large, oblong, and concave, adapted to the condyloid pro- 
cesses of the occiput; and admit of flexion and extension. The 




BONES OF THE TRUNK. 17 

inferior ^oblique processes are round, flat and horizontal, adapted to 
the rotatory motion of the head. The transverse process is extremely 
long. On the inner side of the oblique processes is a tubercle for 
the attachment of the transverse ligament. It has the largest spinal 
foramen. 

The second cervical vertebra is called dentata, from its tooth- 
like process projecting from the upper surface of the body; the 
tip of which is rough for the middle straight ligament, and on 
the sides of the tip there is a flatness for the attachment of the 
moderator ligaments. This process is smooth in front where it 
touches the arch of the atlas and also behind where the transverse 
ligament plays. Upon this process the head rotates. The superior 
oblique process is circular and slightly convex. The spinous process 
is long and bifid. 

The sixth has a long and pointed spinous process. 

The seventh is the largest and resembles a dorsal. The spinous 
process is the longest and tuberculated. The foramen at the base 
of the transverse process does not transmit the vessels. 

DORSAL VERTEBBiE. 

These are twelve in number. The bodies 1 are cylindrical, and 
their transverse diameter decreases from the first to the third, and 
then increases. The upper and lower surfaces are flat, and the sides 
have articular marks 3 for the heads of the ribs. Each fossa is 
formed by two contiguous vertebrae. 
The oblique processes are vertical, -^'xg. 2. 

the superior 8 looking backwards and 
the inferior 9 looking forwards. The 
transverse processes 7 are long, and 
their extremities are enlarged ; in 
front there is an articular face for 
the tubercle of the rib. The spinous 
processes 5 are long and triangular, 
broad at the base, sharp-pointed and 
overlap each other. The spinal fora- 
men is small and round. The inter- 
vertebral foramen is mainly formed 
by the inferior groove, 5 which is 
much deeper than the superior. 4 

The first has a complete fossa for the head of the rib upon 
its side. The eleventh and twelfth have also complete fossae for the 
heads of the ribs. Their transverse processes are short, directed 
backwards, and do not articulate with the ribs. 

LUMBAR VBRTEBRJ. 

Their number is Ave. The bodies are large and oval, the trans- 

2* 




18 



BONES OF THE TRUNK. 



Fig. 3. verse diameter being the longest. 

The spinal foramen is triangular 
and large. The grooves 3 4 form- 
ing the intervertebral foramen are 
also large. The oblique processes 
are vertical ; the superior 7 looking 
inwards and the inferior 8 looking 
outwards. The transverse pro- 
cesses 6 are long and at right angles. 
The spinous 5 processes are short, 

thick, quadrangular, and horizontal. 

The first is the smallest ; the third has the longest transverse 

process ; the fifth has a wedge-shaped body. 




SACRUM. 

Is triangular, and originally consisted of five pieces ; its anterior 

surface is concave, and has four 
Fig. 4. funnel-shaped holes 6 6 on each 

side, transmitting the anterior 
branches of the sacral nerves. 
Its posterior surface is rough and 
convex, and contains the repre- 
sentations of spinous and oblique 
processes. A fissure usually 
exists in place of the fourth and 
fifth spinous processes. There 
are four foramina on each side, 
smaller than those in front, for 
the transmission of the posterior 
branches of the nerves. The 
base has a large oval articular 
mark 1 upon which rests the last 
lumbar vertebra ; it has also two 
oblique processes, and two grooves completing the intervertebral fora- 
mina. 9 The apex 2 is blunt and has a transverse articular surface 3 
for the coccyx. The sides are rough, broader above than below, 
and have a large articular mark for the innominata ; behind this 
surface arise muscles of the back, and below it the sacro-iliac liga- 
ments. The sacral canal runs through the length of the sacrum. 
It is triangular, larger above than below j 6 and is continuous with 
the spinal canal. It contains the cauda equina ; and with it com- 
municate the foramina transmitting the nerves. 




COCCYX. 

The coccyx is flat and triangular, having its base upwards. It 



BONES OF THE TRUNK. 



19 



Fig. 5. 




consists of three or four bones united usually in the 
same curve as that of the sacrum. The pieces are 
frequently united with each other and the sacrum. 

The first piece is the largest, and has two articular 
marks ; behind, it has two cornua ; 23 on its side are 
grooves, 4 5 which with the sacrum complete the canal 
for the fifth sacral nerve. The last piece 6 is a mere 
tubercle. The sides of the coccyx give origin to 
muscles and ligaments. 

PELVIS. 

The pelvis consists of the sacrum, coccyx, and the two innominata 
or hip bones. 

INNOMINATTJM. 

This is a large flat bone forming the haunch or hip of common 
language, resembling in some measure the figure 8. In youth it 




consists of three different parts, united in the acetabulum, viz. the 
ilium, ischium, and pubes. 

Ilium. — This is the largest piece, and forms the wall of the 
upper pelvis. Its external surface is convex and rough, with a semi- 
circular ridge crossing it; above this ridge arises the gluteus medius, 
and below it the gluteus minimus muscle ; the posterior part of 
this surface is the roughest, and gives origin to the gluteus 
maximus. 

The anterior part of the internal surface 6 contains a large, smooth 
concavity called the costa, which gives origin to the iliacus internus; 



20 BONES OF THE TRUNK. 

the posterior is rough and has a large articular mark for the 
sacrum, behind which arise muscles and ligaments. The edge or 
crista is arched and curved like the italic/*. In front there are two 
eminences, one of which is called the anterior superior spinous 
'process,' 7 giving origin to the sartorius and tensor vaginae muscles 
and Poupart's ligament; the other is the anterior inferior spinous 
process, 8, and gives origin to the rectus muscle ; the space between 
the two gives origin to the gluteus medius. Below these processes 
is a large prominence 11 called iliopectineal ; in the groove above 
this passes the iliacus internus and psoas magnus muscles. The 
posterior superior and inferior spinous processes are behind, and to 
them are attached ligaments. The crista has three lips, from the 
internal of which arises the transversalis muscle, from the middle 
arises the internal oblique, and into the external is inserted the exter- 
nal oblique. The inferior border of the ilium presents a notch,? called 
sciatic. 

Ischium. — This is the most inferior part of the innominatum. 
It consists of a body and a branch; the external surface of the body b 
is rough ; the internal surface is smooth, and is called the plane of 
the ischium. The posterior border presents a projection called the 
spine, into which is inserted the lesser sacro-sciatic ligament, and 
beneath the spine is a groove in which plays the tendon of the 
obturator internus muscle. The inferior portion of the body is 
called the tuberosity, from which arise the semi-membranosus, semi- 
tendinosus, and the long head of the biceps muscles ; in front there 
is a ridge into which is inserted the greater sacro-sciatic ligament; 
outside of the ridge is the origin of the adductor magnus muscle. 

The ramus or branch is short and thick, and ascends forward and 
inward, joining the ramus of the pubes, and forming a portion of 
the pubic arch; 9 externally it is rough, and internally it is smooth, 
whence arises the cms of the penis. 

Pubes. — It forms the anterior boundary of the pelvis, 6 and con- 
sists of a body and descending ramus or branch. 

The body articulates with its fellow by a vertical surface/ called 
the symphysis. The superior portion of the body at right angles 
with the symphysis is horizontal^ and limited externally by a pro- 
jection' called the spinous process; from this process there diverge 
two ridges ; the posterior k is sharp and called the crista of the pubes, 
or linea pectinea ; to it is attached a portion of Poupart's and Hey's 
ligament. Between these ridges is included a triangular space, 
the base being the ilio-pectineal eminence, 11 and the apex of the 
spinous process; from this space arises the pectineus muscle, and 
over it pass the femoral vessels. The anterior ridge terminates at 
the acetabulum. 

The ramus descends to join that of the ischium, and forms a part 
of the pelvic arch ; externally it is rough for the origin of the ab- 



BONES OP THE TRUNK. 



21 



ductor muscles ; internally it is smooth, and from it arises the eras 
of the penis. 

The acetabulum, 9 is a deep hemispherical concavity upon the 
outer side of the bone for the articulation of the head of the femur. 
The brim of this cavity is notched on the lower edge. In the bottom 
of the cavity is a rough depression occupied by a mass of fat, com- 
monly called a gland of Havers. Immediately beneath the ace- 
tabulum is a groove, in which plays the tendon of the external 
obturator muscle. 

The obturator or thyroid foramen, is that large opening in the 
front and lower part of the bone, which is filled up by a membranous 
ligament, with the exception of a groove at its upper part, through 
which pass the obturator vessels and nerve. Its shape is oval in 
males, but triangular in females. 



THORAX. 

This cavity is formed by the dorsal vertebrae, ribs and sternum ; 
its figure is conoidal, flattened in front, and concave behind ; the 
apex presents a cordiform 

opening, and the opening at Fig. 7. 

the base has a large notch 
in front. 

S1EENUM. 

Is an oblong, slightly- 
curved bone, placed in front 
of the thorax. Usually it 
consists of three pieces, but 
in advanced life of but one. 

Thej^rs^or superior bone, 1 
is the thickest, and resem- 
bles in shape a triangle, 
with the corners cut off, 
the base being upwards ; on 
the superior edge is a con- 
cavity for the benefit of the 
movements of the trachea ; 
on each side is a large con- 
cavity for the articulation of 
the clavicle, and below are 

two smaller ones for the articulation of the first and part of the 
second rib. 

Sometimes there are found upon the upper edge of the first bone 
two small spherical bones called Epistemal bones. 

The second bone 3 is longer and narrower than the first, increasing 




22 BONES OF THE TRUNK. 

in breadth in its lower extremity ; its sides present pits for the 
articulation of part of the second, the third, fourth, fifth, sixth, and 
part of the seventh ribs. 

The third bone, 3 is very frequently cartilaginous, and called 
xyphoid or ensiform; its shape varies, sometimes being pointed, and 
sometimes bifurcated ; upon its side is a depression for a portion of 
the seventh rib. 



These are twenty-four in number, twelve on either side ; those 
that articulate with the sternum are called true ribs, and are seven 
in number; the five below them are called false ribs : in some rare 
instances there have been thirteen or eleven ribs on one side. They 
are parallel, and directed obliquely downwards and forwards; each 
having a parabolic curve, and gradually increasing in size until the 
eighth, afterwards gradually diminishing. 

The anterior or sternal extremity is larger and flatter than the 
posterior ; the posterior or vertebral extremity presents a spherical 
head, having two articular surfaces separated by a ridge. The neck 
of the rib is very narrow and its upper edge, which is sharp, has 
inserted into it the internal costotransverse ligament; about one inch 
from the head is the tubercle, a prominence with an articular face, 
for articulation with the transverse process of the vertebra; just 
beyond this is a smaller tubercle, for the insertion of the external 
costotransverse ligament. 

Each rib is twisted and bent ; this bend constitutes the angle of 
the rib ; upon the external surface of the angle is a mark showing 
the insertion of the sacro-lumbalis muscle. The lower edge of the 
rib is thin and cutting, and just within it is a groove, 13 running 
two-thirds of its length, and containing the intercostal vessels and 
nerve. The upper edge is rounded, and upon it are inserted the 
intercostal muscles. 

The first rib is small and semicircular, its surface looking supe- 
riorly and inferiorly; the superior surface has upon its middle a 
slight fossa, for the subclavian artery; in front of this is a roughness 
for the insertion of the scalenus anticus muscle, behind it another 
for the insertion of the scalenus medius; the head has a single 
articular surface, its angle is at the tubercle, and it has no inter- 
costal groove. 

The eleventh and twelfth, 112 are called floating ribs, because they 
are not connected with the others ; they have no tubercles, and their 
heads have but a single articular surface. The twelfth is very short, 
but slightly curved, and has no intercostal groove. 



TJONES OF THE HEAD. 



23 



BONES OF THE HEAD. 
> 

These are twenty-two in number, and are divided into those of 
the cranium, which are eight in number; and those of the face, 
which are fourteen. 

CRANIUM. 



FRONTAL BONE. 



It is usually a single, symmetrical 
Fig. 8. 



This forms the forehead, 
bone, though occasionally di- 
vided by a suture into two 
parts. Its shape resembles 
that of a shell. 

The external surface is con- 
vex, and about the middle 
upon each side there is the 
frontal protuberance, 1 being 
the original centre of ossifi- 
cation ; below this and nearer 
the median line is an oblique 
ridge called the nasal or super- 
ciliary protuberance. 2 The 
inferior edge of the bone is 
formed on either side by the 
orbitary ridge, 3 forming the 
superior boundary of the orbit 
of the eye ; this ridge is termi- 
nated outwardly by the exter- 
nal angular process, 4 just within which is a depression for the 
lachrymal gland, and inwardly by the internal angular 5 process; 
between the internal angular processes is a prominence called the 
nasal spine, 9 which serves as an abutment for the nasal bones. 
Upon this orbitary ridge, half an inch distant from the internal 
angular process, a small depression exists, upon which plays the 
tendon of the superior oblique muscle ; to the outside of this depres- 
sion is a notch or foramen, for the transmission of the supra-orbital 
artery and nerve. 6 

The frontal sinus 7 opens near the internal angular process, and is 
formed by the separation of the tables over the orbitary ridge ; its 
capacity varies, and there are no means of determining it in the 
living being ; it empties into the infundibulum of the ethmoid. 

The internal surface is concave and has numerous depressions 
corresponding with the convolutions of the brain ; in the middle is a 
fossa for the superior longitudinal sinus, and a ridge for the attach- 
ment of the dura mater ; at the bottom of this ridge is the foramen 




24 



BOXES OF THE HEAD. 



csecum, transmitting a vein, which forms the commencement of the 
sinus. 

The orhitar jyrocesses are two horizontal plates, forming the roofs 
of the orbits, separated by a large space, which is occupied by the 
ethmoid bone. The internal edges of these processes have two 
grooves, which are converted into foramina, called ethmoidal or 
orbitary, by the articulation of the ethmoid. Each transmits an 
artery and a vein to the nose. The anterior ethmoidal foramen 
also transmits the internal nasal nerve. 

Laterally the bone articulates with the parietal and sphenoid, in- 
feriorly with the bones of the face and with the ethmoid. 



PARIETAL BOXES. 



These occur in pairs, and form the middle and lateral portions of 

the cranium ; they are quad- 
Fig- 9- rangular. 

The external surface is 
• &iai22jfcW *£■:-.-- . convex, has in its middle the 

parietal protuberance, the cen- 
tre of ossification ; below this 
is the semicircular ridge indi- 
cating the attachments of the 
temporal fascia and muscle. 

The internal surface is con- 
cave, with numerous depres- 
sions for the convolutions of 
the brain, and is also tra- 
versed by furrows showing 
the course of the middle ar- 
tery of the dura mater. The 
superior edge 1 is the thickest 
and much dentated ; when adjusted with its fellow, it forms a deep 
groove for the longitudinal sinus. 5 The parietal foramen, 6 trans- 
mitting a vein, opens in this groove. -Ehe inferior edge 3 is short, 
concave, and squamous, articulating with the temporal. The ante- 
rior inferior angle 7 is long and pointed, articulating with the great 
wing of the sphenoid; the posterior inferior 8 angle is very obtuse, 
and deeply grooved on its internal surface for the lateral sinus. 




OCCIPITAL BOXI. 



This is placed at the posterior and inferior part of the head, and 
is of an oval or trapezoidal shape. 

The external surface is convex, and in some parts rough; near its 
middle is a prominence called the external occipital cross,' 2 from 
which there proceeds on each side a semicircular ridge, 1 to which is 
inserted the sterno-cleido-mastoideus muscle, and from which arise 



BONES OF THE HEAD. 



25 



the trapezius and occipital frontalis. About one inch below is 
another semicircular ridge 4 for the insertion of the superior oblique 
muscle. Between this ridge and the foramen magnum ; the space is 
occupied by the recti postici muscles. Reaching from the external 
occipital cross is a vertical ridge 3 extending to the foramen magnum, 
to which is attached the ligamentum nuchae. The space between the 
superior and inferior semicircular ridges is occupied by the insertion 
of the splenius and complexus muscles. 

The foramen magnum* is oval, its antero-posterior diameter being 
the largest; it transmits the medulla oblongata, spinal accessory 
nerves, and vertebral artery. On either side of the foramen is the 
condyloid process, & an oblong convex surface converging towards its 
fellow, and articulating with the atlas. It is frequently divided by 
a ridge or groove, especially in the young African head. The ante- 
rior condyloid foramen 91 transmits the hypoglossal or ninth nerve, 
the posterior condyloid foramen 7 a vein to the lateral sinus. 

In front of the foramen magnum is the basilar process, 11 the 
extremity of which articulates 
with the sphenoid ; the infe- 
rior surface receives the inser- 
tion of the recti postici and 
superior constrictor muscle of 
the pharynx; the superior 
surface is concave and con- 
tains the medulla oblongata. 

The internal surface is con- 
cave and about its middle has 
an internal occipital cross, 
which is more prominent than 
the external ; from it there 
diverge three grooves, con- 
taining the two lateral and the 
superior longitudinal sinuses ; 
interiorly there proceeds a 
ridge to the foramen magnum 
to which is attached the falx cerebelli. 
divided into four smaller ones ; the two 

posterior lobes of the cerebrum, and the two inferior the hemi 
spheres or lobes of the cerebellum. 

The two superior edges are deeply dentated and articulate with 
the parietal; the two inferior articulate with the temporal. On 
each inferior edge is a prominence called the jugular eminence* in 
front of which is a fossa converted into the posterior foramen lacrum 10 
by articulation with the temporal, through which pass the internal 
jugular vein and the eighth pair of nerves. Upon the inferior sur- 
face of this eminence is inserted the rectus capitis lateralis. 




The concavity is thus 
superior, containing the 



26 BONES OF THE HEAD. 



SPHENOID. 



Situated in the middle and anterior part of the base of the cra- 
nium. The shape resembles a bat ; consists of a body and four 
wings ; a large and small one being placed on each side, besides two 
vertical processes directed downwards. 

The body is in the centre and cuboidal in its shape. On its supe- 
rior surface is a deep pit called sella turcica, 16 which contains the 
pituitary gland. This depression is overhung posteriorly by the 
posterior clinoid process ; 6 on either side are two grooves called sulci 
carotid, for the carotid arteries, and in front there is a prominence 
called processus olivaris, upon which is a transverse groove indicating 
the position of the chiasm of the optic nerves. 

On the anterior view of the body are the orifices of the two sphe- 
noidal cells, separated by a ridge, upon which articulates the nasal 

Fig. 11. 




lamella of the ethmoid bone; they empty into the posterior ethmoidal 
cells, and do not exist in infancy. The inferior surface of the body 
has an elevation in the median line called the processus azygos, by 
which it articulates with the vomer. Posteriorly, the surface is 
rough for articulating with the cuneiform process of the occipital 
bone. 

The small wings 1 are placed in front of the large. They are tri- 
angular, flat, and narrow. Their posterior extremities constitute 
the anterior clinoid processes, which are perforated by the optic 
foramina, 4 ' through which pass the optic nerves and ophthalmic 
artery. They articulate in front with the frontal bone. 

The great wings are separated from the small by the sphenoidal 
fissure or for amen, 7 which transmits the third, fourth, first branch 
of the fifth, and the sixth nerves. 

This wing has three surfaces. The cerebral is concave and has 
numerous depressions for the convolutions of the middle lobe of the 



BONES OP THE HEAD. 27 

cerebrum which lodges in this concavity. It has three foramina. 
The foramen rotundum* transmits the second branch of the fifth 
pair. Behind it, is the foramen ovale, 9 through which passes the 
third branch of the fifth pair. The posterior angle of this surface 
is the spinous process, which is perforated by the foramen spinale, 10 
by which the middle artery of the dura mater enters the cranium. 
Projecting from the inferior surface of this process is another called 
styloid, 11 which gives origin to muscles. 

The external surface is the temporal, which is divided by a ridge, 
and has a process in front ; it is covered by the temporal and exter- 
nal pterygoid muscles. The anterior surface is called the orbital, 
forming a large portion of the orbit of the eye. On the superior 
surface is a large, triangular, serrated surface, for articulating with 
the frontal bone ; laterally it articulates with the temporal. 

Pterygoid processes. — These project downwards on either side in 
a line parallel to the facial line, and articulate with the palate bones 
in front. Posteriorly, there is a fossa called pterygoid, which ter- 
minates in a notch, and divides the process into an external and 
internal plate. The external™ is the broader, and gives origin to 
the external pterygoid muscle ) the internal 1 * is the longer, and 
terminates in a hook-like process, called the hamulus, over which 
plays the tendon of the circumflexus palati muscle. The internal 
plate gives origin to the internal pterygoid muscle, which occupies 
a portion of the fossa. 

The internal surface of the base of the pterygoid process has a 
groove upon it, showing the course and connexion of the cartila- 
ginous portion of the Eustachian tube. The pterygoid foramen 1 * 
perforates the base of the process, and transmits the vidian or recur- 
rent nerve. 

TEMPORAL BONES. 

These are placed on either side of the cranium below the parietal 
bone. They consist of three portions, squamous, petrous, and mastoid. 

The squamous 1 is thin and shell-like. Its external surface is 
slightly convex, has grooves for the deep temporal artery, and is 
covered by the temporal muscle. Projecting anteriorly from the 
lower part of this surface is the zygomatic process, 6 which forms a 
part of the zygomatic arch. The base of this process is triangular, 
and has beneath it a cavity called glenoid for the articulation of the 
lower jaw. This cavity is separated by the Grlaserian fissure from 
another behind it, containing a portion of the parotid gland. Through 
this fissure pass the chorda tympani nerve and the laxator tympani 
muscle, attached to the processus gracilis of the malleus. The 
internal surface has a distinct groove 4 for the middle artery of the 
dura mater. The edge is thin and cutting and has flat serrations 5 
for the parietal bone. 



28 



BONES OP THE HEAD. 




The mastoid- portion is behind, and nipple-like. It is thick and 

cellular; the cells being lined 
Fig- 12. by a thin membrane. Exter- 

nally it is rough, and has a 
large process called mastoid, 
upon which are inserted the 
sterno-cleido-mastoid and tra- 
chelo-mastoid muscles. Beneath 
this process is the digastric 
fossa, 7 which gives origin to 
the digastric muscle. Internally 
is a deep sulcus 8 containing a 
part of the lateral sinus. The 
edges are thick and dentate. 
Near the upper edge is the 
mastoid foramen, 2 which trans- 
mits a vein. 
The petrous* portion is pyramidal and directed obliquely forwards 
and inwards. Its structure is extremely dense. 

The base has a large oval opening externally, between the zygo- 
matic and mastoid, called the external meatus, which is surrounded 
by a rim called the auditor?/ process, to which is attached the carti- 
laginous portion of the ear. In the ibetus it is a ring. The apex is 
obtuse and is perforated by the carotid canal. In the angle 
between the apex and the squamous portion, is the bony portion 
of the Eustachian tube, and above it a canal for the tensor tympani 
muscle. 

The inferior surface presents a large process, styloid,** projecting 
from a ridge called vaginal process. Behind it, is the stylo-mastoid 
foramen,' 15 the orifice of the Fallopian canal, which transmits the 
facial nerve and stylo-mastoid artery. Inwards from the styloid 
process is the jugular fossa, which is converted into the posterior 
foramen lacerum by the articulation of the occipital bone; this 
foramen transmits the internal jugular vein and the eighth pair of 
nerves. The tympanic canal, containing Jacobson's nerve, opens 
in this fossa; its other orifice is near that of the Eustachian tube. 
In front of the jugular fossa is the commencement of the carotid 
canal,* 6 which contains the carotid artery and the ganglion of Lau- 
monier. Upon the septum between the jugular fossa and carotid 
canal, is the entrance to the aqueduct of the cochlea. 

The anterior surface presents a groove leading to a foramen 
called hiatus Fallopii, which transmits the superficial petrous nerve, 
a branch of the vidian; behind this is the eminentia arcuata, made 
by the prominence of the labyrinth. At the internal edge is a 
groove for the superior petrosal sinus, and near the apex a semi- 
lunar depression for the ganglion of Casser. 



BONES OF THE HEAD. 29 

The posterior surface has a large opening near the middle, in- 
ternal meatus auditorius; it is not deep, and the base is cribriform. 
Immediately above it is a foramen or fissure for the attachment of 
the dura mater and a small vessel ; behind it is a ridge produced by 
the inferior semicircular canal, and half an inch behind it is the 
aqueduct of the vestibule, concealed by an osseous lamella. 

ETHMOID. 

Is so called from its resemblance to a sieve. It is placed in the 
median line, at the base of the skull, in front of the sphenoid bone, 
and between the orbitar processes of the frontal. Is cuboidal in 
shape and cellular in structure. 

The superior surface is called the cribriform plate? which is per- 
forated with holes for the transmission of filaments of the olfactory 
nerve ; the most anterior hole is the largest, and transmits the in- 
ternal nasal nerve. From the median line is a narrow, triangular, 
hollow process called the crista galli, 3 and to it is attached the falx 
cerebri. In front of this is sometimes the foramen or groove called 
foramen caecum, which admits of the passage of a small vein from 
the nose. 

The bone is divided longitudinally into two halves by the vertical 
plate of bone called the nasal lamella; 1 this can best be seen by 
examining the inferior surface. . It articulates below with the 
vomer, and behind with the crista sphenoidalis. 

The lateral surfaces of the bone are called the ossa plana. The 
os planum is extremely thin and papy- 
raceous, forming a large part of the orbit Fi S- 13# 
of the eye. On its upper edge are two 
grooves, which are converted into two 
foramina, called internal orbitary or 
ethmoidal; the anterior transmits an ar- 
tery, vein, and the internal nasal nerve ; 
and the posterior transmits an artery and 
vein. The inferior edge articulates with 
the superior maxillary bone. When the 
bone is viewed from behind there will be 
seen two scrolls or shells on either side of 
the nasal lamella, but attached to the in- 
ternal face of the os planum. They are 
the superior* and middle turbinated bones? placed one above the 
other, and separated by a fissure. This fissure is the superior 
meatus 6 of the nose. The middle meatus is a space observed in an 
articulated head between the middle and inferior turbinated bones. 
The anterior cells of the ethmoid bone empty into the middle 
meatus ; the most anterior of these cells is funnel-shaped (infun- 
didum), and receives the fluid from the frontal sinus; from the 

3* 




30 



BONES OF THE FACE. 



inferior part of these cells there proceeds a hook-like process. The 
posterior ethmoidal cells and the sphenoidal sinns empty in the 
superior meatus. 

In children there is attached to the ethmoid bone, on each side, 
a hollow triangular process, called the pyramid of Wistar, or cornu 
Bertini. The base is connected with the superior turbinated bone, 
the posterior edge of the cribriform plate, and the posterior edge of 
nasal lamella. The apex lies under the body of the sphenoid bone, 
on each side of the processus azygos. These pyramids are detached 
from the ethmoid in after life, and become the sphenoidal sinuses. 

The ethmoid articulates with the frontal, sphenoid, inferior tur- 
binate, upper jaw, nasal, lachrymal, palate bones, and vomer. 

BONES OF THE FACE. 

These are fourteen in number, and exist in pairs with the excep- 
tion of two, the lower jaw and the vomer. 



SUPERIOR MAXILLARY BONE. 

This with its fellow constitutes the upper jaw. It articulates 

with all the bones of the face 
Fig. 14. with the exception of the lower 

jaw. It has an irregular cubical 
body and four processes. The 
body is hollow and has four 
surfaces. 

The anterior or facial sur- 
face is bounded above by the 
inferior margin of the orbit, 
beneath which is the infra- 
orbital foramen, transmitting 
the infra-orbital nerve, artery, 
and vein. Contiguous to this 
foramen is a depression, called 
the canine fossa, which gives 
origin to the levator anguli 
oris muscle. The posterior or 
temporal surface is rounded. The most prominent part is called the 
tuber™ which is rough and perforated by several small foramina 
which transmit the posterior dental nerve, artery, and vein, to the 
floor of the antrum. 

The superior or orbital surface is triangular, and traversed by the 
infra-orbital groove leading to the foramen of that name. Upon 
the internal or nasal surface is the large opening of the antrum 
Mighmorianum, 1 which is a pyramidal cavity with thin walls; the 
walls are grooved, indicating the passage of the anterior and pos- 




BONES OF THE FACE. 31 

terior dental nerves. The opening is diminished by the articulation 
of the palate, inferior turbinate, and unguiform bones, to a small 
orifice which opens into the middle meatus of the nose. 

The nasal process 4 " arises from the superior and anterior part of 
the bone. It is broad and thin below; externally it gives origin to 
the levator labii superioris alaeque nasi muscle, internally it has a 
transverse ridge dividing the surface unequally for the inferior 
turbinated bone. The anterior edge articulates with the nasal bone, 
the superior with the frontal, and the posterior edge has a deep 
groove, which is converted into a bony canal for the lachrymal sac 
by the articulation of the os unguis. 

The malar process is a rough process upon the external and supe- 
rior part of the bone for articulation with the malar bone. 

The alveolar process contains the sockets for eight teeth. 

The palate process' 7 is the horizontal roof of the mouth and floor 
of the nose ; uniting behind with the horizontal part of the palate 
bone, 10 and on the side with its fellow, from which latter junction 
or suture there arises the nasal crista, for the articulation of the 
vomer. The anterior extremity 6 is the anterior nasal spine. Im- 
mediately behind this is the foramen incisivum for the naso- 
palatine nerve and ganglion of Cloquet. 

PALATE BONE. 

Situated on each side between the superior maxillary and the 
sphenoid bone ; the figure is irregular and consists of three parts. 

The horizontal part 1 is quadrilateral in its shape and assists in 
forming the floor of the nostril and roof of the mouth. The suture 
between it and its fellow forms a part of the nasal crista for the 
articulation of the vomer, and posteriorly is elongated into the pos- 
terior nasal spine ; from which arises the azygos uvulae muscle. 

The ascending or vertical portion* is divided on its internal or 
nasal face by a ridge, 6 for the articulation of 
the inferior turbinated bone; externally it 
has a rough articular surface for the superior 
maxillary bone; upon this surface is a groove, 
converted into the posterior palatine foramen 
or canal by this articulation, which transmits 
the palatine nerve and artery. Posteriorly 
there is an elongated triangular process called 
pterygoid ; 3 this process has three grooves, 
the middle of which forms a part of the ptery- 
goid fossa, and those on each side receive the 
external 10 and internal 11 plates of the ptery- 
goid process of the sphenoid. 

The upper extremity of this vertical or nasal portion is formed 
by two processes separated by a notch which is converted into a 




32 



BONES OF THE FACE. 




foramen, called sphenopalatine, 7 by articulation with the sphenoid 
hone, and transmits the spheno-palatine artery and nerve. The 
anterior process is called orbital, 8 forming a small part of the orbit 
between the ethmoid and superior maxillary. The posterior is the 

pterygoid apophysis; 2 it is ex- 
Fig. 16. tremely thin, inclines inwards 
and fits upon the base of the 
body of the sphenoid. 

MALAR BONE. 

Is quadrangular in shape, and 
forms the prominence of the cheek. 
It consists of a body and pro- 
cesses. The body has three sur- 
faces, the external or facial of 
which, has numerous small per- 
forations for arteries 7 and nerves ; 
the internal or orbital is smooth 
and has a notch which limits the 
spheno-maxillary fissure or fora- 
men lacerum inferius of the orbit; 
the posterior forms the anterior boundary of the temporal or zygo- 
matic fossa. 

The superior process is the frontal,* for articulating with the ex- 
ternal angular process of the frontal bone. The temporal process* 
projects backwards to unite in forming the zygomatic arch. The 
maxillary 5 6 is triangular and rough, for articulating with the malar 
process of the superior maxillary bone. The bone has four edges. 
The superior 3 is curved and continuous with the orbital ridge, the 
inferior gives origin to the zygomatic and masseter muscles, the 
anterior articulates with the superior maxillary, and the posterior has 
the temporal fascia connected with it. 

The malar bone sometimes contains a cavity called the sinus 
jugalis, especially in Mongolians and Malays. 

NASAL BONE. 

These bones unite with each other 2 and are placed between the 
nasal processes of the superior maxillary bones. The shape is a 
long quadrangle, but in Africans it is frequently triangular. The 
superior extremity is narrow and thick, articulating with the frontal 
bone. The inferior is thinner and broader, having the cartilage of 
the nose attached ; the internal edge articulates with its fellow, and 
the external has a spiral groove, whereby it is overlapped by the 
nasal process of the superior maxillary above, and overlaps the pro- 
cess below. The anterior surface has numerous foramina for nutri- 
tious vessels ; the posterior contains a groove for the internal nasal 
nerve. 



BONES OF THE FACE. 33 



UNGUIFORM BONE. 



This is so called from its resemblance to a finger nail (unguis) : 
it is also called lachrymal. It is quadrangular, flat, and small, ex- 
tremely thin and often cribriform. The external surface 1 forms a 
portion of the orbit of the eye, and has a groove in 
front, 2 which completes the canal for the lachrymal Fig. 17. 
sac. From its inferior edge there projects a triangular 
process 7 which articulates with inferior turbinated 
bone. The edges 4 5 6 articulate with the frontal, eth- 
moid, and superior maxillary bones. 



INFERIOR TURBINATED 




This is a porous scroll, placed at the inferior part 
of the nasal cavity below the ethmoid. Its posterior 
end is the more pointed. Its internal surface is con- 
vex and looks towards the nose ; the external surface has a broad 
hook, processus maxillari§, 3 which enters the antrum Highmorianum, 
and partly closes it. The superior edge has a triangular process 
called lachrymal, which articulates with the unguis. The portions 
of the edge in front of and behind this process rest upon ridges of the 
nasal process of the superior maxillary and palate bones; there is 
frequently a process upon this edge which unites it with the ethmoid 
bone. 



A single bone, forming a large portion of the nasal septum, con- 
sisting of two plates of compact structure. It is a flat bone with 
four edges. The superior is the thickest, having a deep groove 
between two lips (alse) for the reception of the processus azygos of 
the sphenoid. The inferior edge is the longest, articulating with 
the nasal crista of the palate suture. The anterior unites with the 
nasal lamella of the ethmoid, and the posterior is thin, sharp, and 
concave, separating the posterior openings of the nose. 

INFERIOR MAXILLARY. 

Is also single, having a parabolic curve ; placed at the inferior 
portion of the face. It consists of a body and two rami. The body 
is convex in front and presents in its middle the anterior mental 
tubercle or spine, which in youthful life is a suture. On either side 
of this is a large hole, called the anterior mental 5 foramen, trans- 
mitting a part of the inferior alveolar artery and nerve. The por- 
tion of the bone between these two foramina is called the chin. The 
posterior surface of the chin is concave and has the posterior mental 
tubercle in its middle, upon which are two marks on each side, for 
the genio-hyoglossus and genio-hyoid muscles; on either side of 



34 



OF THE HEAD IN GENERAL. 



this tubercle or spine is a fossa for the insertion of the digastricus. 
Extending backwards from this tubercle, is a ridge 9 called mylo- 
hyoid, for the muscle of that name ; above this ridge is a shallow 
fossa for the sublingual gland; below it and behind, is a larger 

one for the submaxillary gland. 
Fig- 18. The alveolar process, contains 

sockets for sixteen teeth. The 
inferior edge is the base, which is 
thicker in front, and has two 
corners giving a squareness to 
the chin. 

The ramus 2 is square, and at 
^ - l*\ ^>^Si^fervw right angles to the body in man- 
hood : in youth and old age it is 
oblique j externally it is rough for 
the masseter muscle, anterior to 
which is a groove for the facial 
artery." The internal face has a 
posterior mental foramen, 13 for the 
entrance of the inferior alveolar artery and nerve. To the edge of 
this foramen is attached the internal lateral ligament ; near it is a 
groove 14 transmitting the mylo-hyoidean nerve ; below, is the sur- 
face for the insertion of the internal pterygoid muscle. The angle 8 
is rough, and has attached to it the stylo-maxillary ligament. The an- 
terior edge of the ramus is continued into the external oblique ridge. 6 
The superior part of the ramus has two processes separated by 12 
the sigmoid notch. The coronoid process is in front, 10 and is trian- 
gular and thin j it has inserted into its apex the temporal muscle ; 
in front there is a groove for the buccinator muscle. The posterior 
is the condyle 11 articulating in the glenoid cavity of the temporal 
bone. The neck is narrow, and on the inside of it is a fossa for the 
insertion of the external pterygoid muscle. 




OF THE HEAD IN GENERAL. 

Sutures. — The principal sutures of the head are the coronal, which 
unites the parietal and frontal bones; the saggital, which unites 
the two parietal bones in the adult, and in a child extends to the 
root of the nose ; the occipital, which joins the parietal and occi- 
pital bones; and the squamous, uniting the squamous part of the 
temporal and the parietal bones. Besides these there are others 
uniting the bones of the face. That part of the suture between the 
mastoid and parietal bones, is called additamentum suturae squa- 
mosa ; and that suture between the mastoid and occipital, is called 
additamentum suturae occipitalis. 

Fontanels. — These are the deficiencies in ossification in the bones 



OF THE HEAD IN GENERAL. 35 

of the foetal head. , The anterior is large and quadrangular, situated 
at the junction of the coronal and saggital sutures. The anterior 
angle is the most elongated. The posterior is small and triangular, 
and situated at the junction of the lambdoidal and sagittal sutures. 
Besides these there are two smaller fontanels on either side ; one is 
in the angle of the temporal, parietal, and occipital bones, and the 
other is at the junction of the temporal, parietal, and sphenoid 
hones. 

Ossa Wormiana or Triquetral, are small bones, irregular in shape 
and number, sometimes found in the sutures, particularly about the 
middle of the lambdoidal. They have a distinct point of ossifica- 
tion. 

The diploe is the cellular bony structure between the external and 
internal or vitreous tables j it is traversed by channels lined by a 
venous lining which empty partly into the sinuses of the dura 
mater and partly into the emissaries of Santorini. 

The cavity of the cranium is about six and a half inches in length, 
five in breadth and five in height. When the calvaria or arch of the 
cranium is removed, three deep fossas are observed at the base on 
each side. The anterior is formed by the frontal, sphenoid, and 
ethmoid bones, and contains the anterior lobes of the brain j the 
middle is formed by the sphenoid and temporal bones, and lodges 
the middle lobe ; the posterior is formed by the occipital and tem- 
poral bones, and contains the cerebellum. 

Orbital cavity. — Is formed on each side by seven bones. 

The cavity is conical, the apex being formed by the optic foramen ; 
the base looks outwards and is somewhat quadrangular. The sphe- 
noidal foramen or fissure opens into the orbit, and is also called 
foramen lacerum superius ; another slit or fissure between the sphe- 
noid and maxillary bones being the foramen lacerum inferius. Be- 
sides these there are other openings into the orbit already mentioned 
in the description of each bone. 

Nasal Cavity. — This is an irregular cavity, separated from its 
fellow by the nasal septum. It has three distinct passages or mea- 
tuses. The superior is between the superior and middle turbinated 
bones, and has opening into it the posterior ethmoidal cells, the 
sphenoidal cells, and the spheno-palatine foramen; the middle is 
between the middle and inferior turbinated bones, and has opening 
into it the frontal sinus, anterior ethmoidal cells, and the antrum, 
usually. The inferior is the largest, and between the inferior tur- 
binated bone and the floor of the cavity ; into it opens the nasal 
duct. The opening into the nasal cavity in front is called the an- 
terior nares ; the opening behind posterior nares. 

Zygomatic fossa, also called temporal, is the large fossa on either 
side of the head, formed by the parietal, sphenoid, temporal, and 
frontal bones, and bounded externally by the zygoma. The tem- 
poral muscle occupies nearly the whole. 



36 OP THE HEAD IN GENERAL. 

Ptery go-Maxillary Fossa or Fissure. — This is at the bottom of 
the zygomatic fossa, and formed by the sphenoid, palate, and supe- 
rior maxillary bones. It is triangular, and the base is upwards. 
The ganglion of Meckel is contained in it, -which gives off branches 
going through the foramina which open upon this fossa. It is con- 
tinuous with the foramen lacerum inferius or spheno-maxillary slit. 

Facial Angle. — This is formed by drawing a straight line from 
the lower part of the frontal bone to the anterior nasal spine, and 
intersecting it at this latter point by another drawn through the ex- 
ternal meatus auditorius. It establishes a relation between the 
cranium and the face. The smaller the angle the more inferior is 
the conformation. By comparing the heads of the great races of 
the world, it is found to be 80° to 85° in Europeans, 75° in the 
copper-coloured or Mongolians, and 70° in Negroes. 

In the African head these additional peculiarities will frequently 
be found. The temporal fossa is large, and the temporal ridges are 
nearly approximated. 

The pterygoid processes of the sphenoid project in a line parallel 
with the facial line and thereby alter the shape of the posterior 
nares. 

The condyloid processes of the occiput are often divided into two 
portions by a ridge or groove. 

The lower boundary of the anterior nares is deficient in a sharp 
ridge which characterizes the Caucasian head. In these peculiar 
features the African adult head seems permanently to retain marks 
which are generally found to belong to the fetal head. 

HYOID BONE. 
This bone is situated in the neck and connected with the root of the 
tongue and upper part of the larynx. It 
Fig. 19. is shaped like the Greek v, the convexity 

being in front. It does not articulate 
with any other bone. It consists of a 
body and four cornua. The body 1 is 
quadrilateral, convex in front, and con- 
cave behind. The front surface gives 
origin and insertion to muscles of the 
neck, and has a well-marked projec- 
tion. The greater cornua 2 are about an 
inch in length, and in early life united to the body by means of 
cartilage and ligaments ; they are flattened, project backwards, and 
terminate in a head or tubercle. They give origin and insertion to 
muscles of the neck. The lesser cornua* are attached at the junc- 
tion of the body and great cornua ; they are cartilaginous usually, 
and of a few lines in length. To them are attached the stylo-hyoid 
ligaments. 




UPPER EXTREMITY. 



37 



UPPER EXTREMITY. 

The upper extremity is divided into the shoulder, arm, forearm, 
and hand. 

The shoulder consists of two bones, the scapula and the clavicle. 

Scapula. — The shoulder blade of common language. Placed on 
the back part of the thorax between the second and seventh ribs. 
It is thin, flat, and triangular ; has two surfaces, three edges, and 
three angles. 

The anterior face is a concavity called costa or venter, divided by 
ridges, and giving origin to the subscapular muscle. The posterior 
face is the dorsum, divided by the spine into two fossae ; the fossa 
supra-spinata, 1 giving origin to the supra-spinatus muscle, and the 
fossa infra-spinata, 3 giving origin to the infra-spinatus muscle. 

The spine 10 is a rough ridge running obliquely across the dorsum, 
and terminating in the acromion process. The edge of the spine 
gives origin to the deltoid, and insertion to the trapezius muscles ; 
near the base of the scapula the spine has a small triangular sur- 
face, 11 over which plays the trapezius tendon. The acromion pro- 
cess is flat and triangular, has a small articular mark 12 in front for 
articulation with the clavicle. 

Internal edge or base. — Is the longest, and nearly parallel 9 with 
the vertebral column ; has an external lip for the insertion of the 
rhomboid muscles, and an internal one for the serratus anticus. 

External edge. — Is thick, 5 and contains a fossa giving origin to 
the teres minor muscle. At the 
upper part of this fossa is a rough Pig. 20. 

mark for the origin 8 of the long 
head of the triceps. 

Superior edge. — Is thin and 
small, 3 and has a notch called eora- 
coid, 4 which is converted into a fora- 
men by a ligament, and transmits 
the supra-scapular artery and nerve. 
Near this notch arises the omo-hyoid 
muscle. 

Superior angle. — Almost a right 
angle, and has the levator anguli 
muscle inserted into it. 
- Inferior angle. — Is the most point- 
ed, 7 and gives origin by its posterior 
surface to the teres major muscle, 
and is connected with the latissimus 
dorsi. 

External angle. — Presents a large 
articular cavity, 6 called glenoid, upon 

4 




38 CLAVICLE — HUMERUS. 

a narrow neck. This cavity is oval and shallow; and at its summit 
is a mark showing the origin of the long head of the biceps mnscle. 
Coracoid process. — This projects forwards and outwards from the 
neck, 14 in a curved manner. Its tip has marks for the insertion of 
the pectoralis minor and also for the origin of short head of the 
biceps and coraco-brachialis. Its base has a tubercle to which is 
attached the conoid ligament. 

C IATIC LE. 

A long bone placed transversely at the upper and anterior part 
of the thorax, resembling in shape the italic f. It articulates 
with the sternum and scapula. The sternal two-thirds is convex 
anteriorly, and the humeral third concave anteriorly. The upper 
surface has a depression near the sternal extremity, showing the 
origin of the sterno-eleido-mastoid muscle. The inferior surface 
has a roughness near the sternal extremity for the rhomboid or 
costo-clavicular ligament, and near the humeral extremity a tubercle 
and ridge for the coraco-clavicular ligament ; the space between 
these two marks is for the insertion of the subclavius muscle. The 
anterior edge gives origin by its sternal two-thirds to the pectoralis 
major, and by its humeral third to the deltoid. The '.posterior edge 
has a foramen for the nutritious artery. 

The sternal extremity is thick and triangular, with a surface for 
articulation with the sternum ; the posterior and inferior corner of 
it is elongated, which contributes to the strength of the articulation. 
The humeral extremity is fiat and spongy, with an articular face for 
the acromion process of the scapula. 

In the male the bone is shorter, thicker, and more curved than 
in the female. 

HUHBSUS. 

The arm-bone is cylindrical, and reaches from the shoulder to the 
elbow. The superior extremity presents a hemispherical head- for 
articulation with the glenoid cavity of the scapula, separated by a 
deep groove, the anatomical neck, 3 from the shaft of the bone. Below 
this groove are two tuberosities; the greater, 4 is the external, 
and has three facets for the insertion of the supra and infra- 
spinatus, and teres minor muscles; the lesser, on the inner side, 5 is 
for the insertion of the subscapularis. These tuberosities are sepa- 
rated from each other by a groove, 6 called bicipital, in which plays 
the tendon of the long head of the biceps muscle. The anterior or 
external edge 7 of this groove has the pectoralis major muscle inserted 
into it, and the posterior 8 or internal edge, receives the latissimus and 
teres major muscles. The surgical neck is between the insertion of 
these muscles and the anatomical neck of the humerus. About the 
middle of the shaft, and upon its outer side, is a triangular roughness 9 



ULNA. 



39 



for the insertion of the deltoid ; on the inner side 
and a little below* is a ridge for the insertion of 
the coraco-brachialis : 10 below this ridge is the 
nutritious foramen, and above it is a shallow 
spiral groove for the musculo-spiral nerve and 
profunda major artery. 

The inferior extremity is flat and broad ; an- 
teriorly it is covered by the brachialis anticus 
muscle, and posteriorly by the triceps. Ex- 
ternally, there is a ridge 16 leading to the external 
condyle,™ from which arise the supinator and ex- 
tensor muscles. Internally a ridge 15 leads to the 
internal condyle, 1 * which is more prominent than 
the external, and from which arise the flexor mus- 
cles of the forearm and the pronator radii teres. 

The articular surface at the elbow consists of 
a hemispherical head 11 for the radius, and an 
irregular cylinder 13 for the ulna. Above this 
articular surface, and in front, is a fossa, 17 called 
the lesser sigmoid cavity, which receives the coro- 
noid process of the ulna in extreme flexion; 
behind is a larger fossa, the greater sigmoid, for 
the olecranon in extreme extension. Sometimes 
these fossas are connected by an opening. 



Fig. 



The forearm consists of two bones — Kadius and 
Ulna. 

The Ulna is the longer, and is placed on the 
inner side, reaching from the elbow to the wrist. 

The upper extremity is the larger, and has 
a hook-like process behind, 4 called olecranon, 
to which is inserted the triceps extensor cubiti. 
In front, is the coronoid process, 5 the base of 
which has a roughness for the insertion of 
the brachialis anticus muscle. Between the ole- 
cranon and coronoid processes, is the greater sig- 
moid cavity, 3 for articulation with the humerus : 
continuous with this is the lesser sigmoid cavity, 3 
upon the outside of the coronoid process, for the 
articulation of the head of the radius. Behind 
the lesser sigmoid cavity, is a triangular, uneven 
surface, for the insertion of the anconeus muscle. 
This surface is limited by a ridge giving origin 
to the supinator radii brevis muscle. 

The body is prismatic ; the anterior surface 1 is 
occupied in its upper three-fourths by the flexor 
profundus, and in the lowest fourth, by the pro- 




40 RADIUS. 

nator quadratus muscle. The posterior surface is occupied by the 
extensors of the thumb and the indicator muscle. 

The external edge 7 is the sharpest, and to it is attached the in- 
terosseous ligament. 

The lower extremity has a small rounded head, 8 the outer side of 
which has a smooth articular surface for the radius. From the 
inner side, there projects 9 the styloid process, to which is attached 
the internal lateral ligament j behind this process is a groove, in 
which glides the tendon of the extensor carpi ulnaris muscle. 

b. adiu s. 

It is placed on the outer side of the ulna, and is slightly curved 
and prismatic. 

The superior extremity has a rounded head, 11 the rim of which is 
smooth. The internal part plays in the lesser sigmoid cavity. The 
upper surface of the head has a cup-like depression for articulation 
with the humerus. Beneath the head is the neck, 12 the narrowest 
part of the bone. Below the neck, and on the inner side, is the 
tubercle,* 3 rough below and smooth above, for the insertion of the 
biceps muscle. 

The body is prismatic; anteriorly, the surface gradually increases 
in breadth, 10 giving origin to the flexor longus pollicis, and receiving 
the insertion of the pronator quadratus muscle. The posterior sur- 
face is occupied by the extensor major of the thumb and the indi- 
cator muscles. The external surface is curved, and has a roughness 
about the middle for the insertion of the pronator radii teres muscle, 
above which and below the tubercle is the space occupied by the 
insertion of the supinator radii brevis muscle. 

The inferior extremity is thick and triangular. The surface of 
the extremity 15 is concave and divided by a ridge. It articulates 
with the scaphoid and lunare. Continuous with this articular sur- 
face, is a smaller one on the internal aspect of the extremity for the 
articulation of the ulna. Externally there is a styloid process, l6 for 
the attachment of the external lateral ligament. 

Near a ridge which terminates in the styloid process, is inserted 
the supinator radii longus. Upon the dorsal view of this extremity 
of the bone, are three large grooves, each divided into smaller ones. 
The groove near the supinator ridge transmits the tendons of the 
extensor ossis metacarpi pollicis and the extensor minor pollicis ; the 
groove in the middle is the broadest and most shallow, transmitting 
the tendons of the radial extensors j and the groove nearest the ulna 
transmits the tendons of the extensor communis, indicator, and exten- 
sor major pollicis. The portion of the groove occupied by the latter 
is very deep. 



CARPUS. 



41 



Fig. 23. 



HAND. 

The harid consists of the carpus, metacarpus, and digiti. 

The carpus or wrist is oblong, the greatest diameter being trans- 
verse. The dorsal surface is convex, and the palmar surface is 
concave, with four prominences. This concavity transmits the flexor 
tendons. 

It consists of eight bones arrayed in two rows. The bones of the 
superior row are the scaphoid, lunare, cuneiform, and pisiform. 
Those of the inferior row are the trapezium, trapezoides, magnum, 
and unciform. 

Scaphoid, is on the radial side, and resembles a boat; has a large 
convex surface superiorly for the ra- 
dius, and inferiorly a deep concavity 
for the magnum. It articulates in 
front with the trapezium and trape- 
zoides, and on the inside with the 
lunar e. 

Lunare, of a crescentic figure, has 
a convex surface superiorly for the 
radius, and a concavity in front for 
the magnum, articulates on the inside 
with the cuneiform. 

Cuneiform. — Wedge-shaped, or py- 
ramidal. Inferiorly it articulates with 
the unciform. Distinguished by a 
circular facet on its palmar surface 
for the pisiform. 

Pisiform. — Pea-like bone, forms 
one of the prominences in the palm 

of the hand, has the flexor carpi ulnaris muscle inserted into it, and 
has but one articular mark, which is for the cuneiform. It is the 
smallest bone of the carpus. 

Trapezium, has the most numerous surfaces and angles. The 
largest articular surface is for the thumb; two others, joining each 
other, are for the scaphoid and trapezoides. On the palmar surface 
is a ridge and a deep groove for the flexor carpi radialis tendon. 

Trapezoides, is the smallest bone of this row. It is a four-sided 
pyramid with its apex towards the palm; its dorsal surface is the 
base and inclines inwards. 

Magnum. — The largest bone of the wrist. Has a rounded head 
looking backwards ; the body is quadrilateral. 

Unciform. — Distinguished by a hook-like process, resembling a 
nail, on its palmar surface, which gives origin to the flexor brevis 
minimi digiti. 

4* 




42 



FIN GEES. 



METACARPUS. 

Consists of fire bones, each having a head, shaft, and base. 
The head is rounded, articulating with the first phalanx; a rough- 
ness on each side indicates the attachment of the lateral ligament. 

The base is the superior extremity, rough, and quadrilateral, 
having articular marks on the extremity and either side. 

The body or shaft is prismoid, having impressions on its sides for 
the interossei muscles. 

The first is short and thick, and belongs to the thumb. Its base 
has but one articular surface, and that is for the trapezium. Its 
head is Dot very spherical, and its palmar surface articulates with 
the sesamoid bones. 

The second is the longest, and belongs to the index finger; it has 
a notch at its base for articulating with the trapezoid ; and a lateral 

articular mark upon one side only : a 
Fig. 2±. mark upon its dorsal surface indicates 

the insertion of the extensor carpi radi- 
alis longior. 

The third has a triangular base with 
an articular mark on each side, and on 
its dorsum one for the extensor carpi 
radialis brevier. 

The fourth is much smaller. The 
external lateral surface of its base is 
double. 

The fifth is the smallest. Its base 
has but one lateral surface, and that is 
external and single. Internally there 
is a tubercle at the base for the exten- 
sor carpi ulnaris. 

r I X G E E s. 

The fingers contain three bones called 
phalanges: the thumb has but two. 

First row. — The phalanges of this row are the largest, convex on 
their dorsal, and flat on the palmar surface. The superior extremity 
has a single concavity for the head of the metacarpal bone. The 
inferior extremity has two convexities separated by a groove. A 
roughness on either side of this extremity, indicates the attachment 
of the lateral ligament. The ridges extending from one extremity 
to the other are for the theca of the flexor tendons. 

Second row. — These are smaller. The superior extremity has 
two concavities, separated by a ridge ; the inferior two convexities, 
separated by a groove. The ridge on either side of the body has 
the theca and tendon of the flexor sublimis attached to it. 

Third row. — These are the smallest, and differ much from the 







FEMUR. 



43 



other rows, having but one articular extremity, which is the superior, 
having two concavities and a ridge. The inferior extremity is flat- 
tened, thin, and rough. 

The middle finger (imjpudicus) is the longest. The ring finger 
(annularis) is the next in size. The forefinger (indicator) is 
thicker than the last. The little finger (auricularis) is the smallest. 

Sesamoid bones. — These are four in number — two being placed 
upon the palmar side of the lower extremity of the metacarpal bone 
of each thumb, in connexion with the short flexor tendon. 

LOWER EXTREMITY. 



The femur is the longest bone in the body, reaching from the 
acetabulum to the knee. 

The superior extremity presents a spherical head, 2 which has a 
depression upon it for the ligamentum teres. The part between the 
head and shaft is the neck, 3 which is shorter and 
more horizontal in old persons and in females. Fig. 25. 

Externally is the trochanter major, a large pro- 
cess having an oval mark in front for the gluteus 
minimus ; and above a double mark for the glu- 
teus medius ; the tip has the pyriformis inserted 
into it, and behind the tip is the digital fossa, 
into which are inserted the gemelli and obturator 
muscles. Below and on the inner side is the 
lesser trochanter, into which is inserted the psoas 
magnus, and iliacus internus muscles. A ridge 
between the trochanters behind, indicates the in- 
sertion of the quadratus femoris, and a corre- 
sponding one in front 5 , which is less distinct, 
serves for the connexion of the capsular ligament. 

The inferior extremity is broader than the up- 
per, and is divided by a fossa in front, and a 
notch behind, into two condyles. The interned 
condyle seems to be much the longer, 8 and is in 
reality somewhat so ; its internal surface 11 gives 
origin to the internal lateral ligament and its poste- 
rior to the gastrocnemius muscle; its external 
surface assists in forming the notch, and has a 
roughness in front for the posterior crucial liga- 
ment. 

The external condyle contributes by its in- 
ternal surface to form the notch, and has a rough- 
ness behind for the anterior crucial ligament. Its 
posterior surface gives origin to the popliteus, plan- 
taris, and gastrocnemius muscles, and its external 
to the external lateral ligament. The fossa in front, is unequally 



44 



PATELLA TIBIA, 



divided between the condyles, the larger and natter portion belong- 
ing to the external. In this fossa plays the patella. 

"The shaft of the bone is curved anteriorly, and is covered in 
front by the origin of cruraeus muscle. Posteriorly there is a rough 
ridge called linea aspera (Fig. 26) 3 which consists of two lips 
having a tendency to separate above and below. The inner lip 
shows" the insertion of the pectineus muscle. p of the adductor 
brevis/ b and of the adductor magnus. 1 ^ This last insertion occu- 
pies this inner lip in nearly its whole length: so 
Fig. 26. also does the origin of the vastus interims. The 

outer lip has inserted into it the gluteus niaxi- 
nius.=- and also gives origin to the vastus exter- 
num and the short head of the biceps flexor 
cruris. b 



PATELLA. 



- 



The patella is the largest sesamoid bone in the 
body, and commonly called the knee-pan. It is 
flat and triangular ; thick and broad above, and 
thin and pointed below. The anterior surface is 
covered by integument; the posterior is a smooth 
articular- surface divided by a ridge unequally — 
the external portion is the larger and flatter, 
adapted to a corresponding surface of the femur. 

The superior edge is thick, and has the tendon 
of the rectus inserted into it. The inferior is 
| minted, and to it is attached the ligament of the 
patella. 



The tibia is longer and thicker than the fibula. 
I: is placed on the inside of the leg, and com- 
monly called the shin-bone. The superior ex- 
tremity, or head, is large and thick, presenting 
an oval articular surface for the femur. This 
surface is divided by a pyramidal eminence, the 
tus process* into two surfaces, both of which 
are oval, but the internal is longer and deeper ; to the base of this 
spinous process are attached anteriorly and posteriorly the crucial 
ligaments; in a depression npon its summit is fastened the posterior 
end of the external semilunar cartilage. (Tig. 27.) 

An enlargement upon either side of the head are called tuberosi- 
ties or condyles; upon the posterior part of the external condyle 3 is 
a small articular face, looking downwards, for the head of the fibula; 
upon the posterior part of the internal condyle- is a depression for 
the insertion of the semi-membranosus tendon. 



TIBIA. 



45 



Below the head, and in front, is a prominent tubercle 5 for the in- 
sertion of the ligament of the patella, and above it a smoothness 
corresponding with its bursa ; below the head, and behind, is a tri- 
angular surface, 4 occupied by the poplitaeus muscle, limited by an 
oblique ridge 5 (Fig. 28), which gives origin to the soleus muscle. 

The body is prismatic. Its internal surface 6 (Fig. 27) is smooth 
and covered by the skin ; the external surface gives origin to the 
tibialis anticus and extensor communis digitorum; from the posterior 
surface arise the tibialis posticus and flexor communis digitorum. 

The anterior edge 1 (Fig. 27) is sharp and superficial, generally 
curved with some resemblance to the italic f; the external has a 
ridge for the attachment of the interosseous ligament, and the in- 

Fig. 27. Fig. 28. 




agifi 



ternal is rounded, having the sartorius, gracilis, and semi-tendinosus 
inserted into it at its upper part. 

The inferior extremity is smaller than the superior, and four- 
sided. Over the anterior surface pass the extensor tendons; on the 
posterior is a slight fossa 9 (Fig. 28) for the tendon of the flexor 
longus pollicis ; externally there is a rough triangular fossa for the 
articulation of the fibula ; and internally there is a large process, 
called the internal malleolus* (Fig. 28), behind which is an oblique 



46 



FOOT. 



fossa, transmitting the tendons of the tibialis posticus and flexor 
longus digitorum pedis. The inferior extremity of the malleolus 
is notched for the attachment of the internal lateral ligament ; its 
internal surface is superficial; its external surface is continuous 
with the quadrangular concavity at the extremity of the bone, for 
the articulation of the astragalus. 

FIBULA. 

The fibula is a long thin bone placed upon the outside of the leg, 
and somewhat posteriorly at the upper part (Fig. 27 9 , Fig. 28 10 ). 
It is slightly twisted in its appearance, and has a convexity back- 
wards. The superior extremity or head is thick and large, and 
articulates with the external condyle of the tibia. External to this 
articular surface, is a mark for the attachment of the external 
lateral ligament of the knee-joint, terminated behind by a styloid 
process, for the insertion of the tendon of the biceps. 

The body is prismatic, and has three surfaces; the external of 
which is the broadest, and commencing upon the anterior part of the 
bone above, winds around it, so as to terminate upon its posterior 
side below. The upper two-thirds of this surface give origin to the 
peroneus longus and brevis ; the lower third terminates in a groove, 
which indicates the course of the tendons of these muscles. The 
internal face looks towards the tibia, and is divided longitudinally 
by a ridge, to which is attached the interosseous 
Fig. 29. ligament; the space in front of which gives 

origin to the extensor proprius pollicis, and 
the extensor communis digitorum; and the 
space behind gives origin to the tibialis posticus. 
The posterior surface is also spiral, and gives 
origin to the soleus, and the flexor longus 
pollicis muscles. 

The inferior extremity terminates in the ex- 
ternal malleolus, which is longer and flatter 
than the internal. Its external surface is super- 
ficial and triangular ; its internal has a smooth 
articular surface for the astragalus. The ex- 
tremity is pointed, and often called the coronoid 
process, immediately within which is a rough 
depression for the external lateral ligament. 

FOOT. 

It consists of the tarsus, metatarsus, and 
phalanges. The tarsus consists of seven bones, 
viz. : os calcis, astragalus, cuboid, scaphoid, 
and three cuneiform. 

Os Calcis. — This is the largest of the tarsal 
bones, and constitutes the heel. Its figure is longitudinal. Supc- 




FOOT. 47 

riorty it has two articular surfaces for the astragalus, separated by a 
deep groove, in which is fastened the interosseous ligament. The 
posterior portion is convex and the larger of the two. The anterior 
is narrow, concave, and divided by a small groove into two parts. 

The internal surface has a deep concavity, called the sinuosity, 
for the passage of tendons, vessels, and nerves of the sole of 
the foot. The external surface is covered by the skin, and 
has two grooves for the tendons of the peroneus longus and 
brevis. The inferior surface has two tuberosities behind, of which 
the internal is the broader and larger; and also one in front. 
These tuberosities give origin to muscles and ligaments. The 
posterior extremity 3 is rough and prominent in its inferior half, 
into which is inserted the tendo-achillis ; the superior half is 
smooth, corresponding with the bursa. The anterior extremity 
presents two processes, called the greater and lesser apophyses ; the 
greater is external and below, and has a flat triangular articular 
surface for the cuboid bone, surmounted by a rough projection. The 
lesser apophysis (sustentaculum tali) is a blunt hook projecting for- 
wards and upwards, having an articular concavity above, constitu- 
ting that portion of the superior surface of the bone, which articulates 
with the astragalus; upon its inferior surface is a groove for the 
tendon of the flexor longus pollicis. 

Astragalus. 1 — Is next in size to the os calcis. It consists of a 
body and a head. Superiorly the body presents a large articular 
convexity for the tibia j continuous with this, on either side, is an 
articular surface for the malleoli ; that upon the external side is 
the larger ; inferiorly is a concavity, divided by a deep rough groove 
for the interosseous ligament ; posteriorly, is a slight groove for the 
flexor longus pollicis. 

The head 21 is upon the anterior portion of the bone. It presents 
a large anterior convexity, the horizontal diameter of which is the 
greatest. On the internal side of the head is a small triangular sur- 
face, which rests upon the calcaneo-scaphoid ligament. The head 
is united to the body by a narrow portion called the neck, which 
has a depression superiorly and inferiorly. 

Scaphoid. 41 — Is oval, thicker above than it is below; posteriorly 
it has a deep concavity for the head of the astragalus ; anteriorly , 
an articular convexity, divided by ridges into three triangular facets 
for the cuneiform bones. Internally, is a tubercle for the insertion 
of the tibialis posticus tendon ; and externally, there is sometimes a 
small articular face for the cuboid. 

Cuboid. 9 — Placed at the outer portion of the foot, is somewhat 
cuboidal in shape ; superiorly, it is rough and convex ; inferiorly, 
is a prominent ridge for the calcaneo-cuboid ligament, and in front 
of this ridge is a groove, commencing at the external edge, and run- 
ning obliquely forward, in which plays the tendon of the peroneus 



48 METATARSUS. 

longus ; internally, it articulates with the external cuneiform ; an- 
teriorly, with the fourth and fifth metatarsal bones ; posteriorly, is 
a semi-spiral surface for the greater apophysis of the os calcis. 

Internal Cuneiform. 5 — Is the largest of the three cuneiform bones. 
It is wedge-shaped, and is placed upon the inner side of the foot. 
The small extremity of the wedge looks upwards. Its internal sur- 
face is convex, and immediately beneath the skin ; its external sur- 
face is concave, and has articular marks for the second cuneiform 
and the second metatarsal bones; anteriorly, is the largest arti- 
cular surface, for the metatarsal bone of the big toe ; posteriorly, is 
a triangular articular cavity for the astragalus, with the base down- 
wards. The inferior surface of the bone, or the base of the wedge, 
is rounded into a tuberosity ; upon the inner side, is inserted the 
tendon of the tibialis anticus. 

Middle Cuneiform. 5 — Is the smallest of the three, and placed with 
the base of the wedge upwards; anteriorly, it articulates with the 
second metatarsal bone ; posteriorly, it is slightly concave, and arti- 
culates with the scaphoid; internally, it articulates with the internal 
cuneiform, and externally, with the external cuneiform bone. 

External Cuneiform. 1 — Intermediate in size between the two 
last. It is wedge-shaped and base upwards. Anteriorly it articu- 
lates with the third metatarsal bone ; posteriorly there is a quadran- 
gular facet for the scaphoid ; internally it has two articular sur- 
faces, the posterior of which is the larger, and for the internal cunei- 
form bone; the anterior is for the second metatarsal. Externally 
is an angular projection, in front of which is a small facet for the 
fourth metatarsal bone, and behind which is an articular surface for 
the cuboid bone. 

METATARSUS. 

Consists of five parallel long bones, 9 whose heads are rounded 
and articulate with the toes, and whose bases articulate with each 
of the three cuneiform and cuboid bones. There is a roughness on 
each side of the head to which is attached the lateral ligament. 
The necks are narrow. 

First. Is on the inside of the foot, and is easily recognised, being 
the shortest and thickest of the set. Its base is large and articulates 
with the internal cuneiform bone, and has a tubercle below for the 
insertion of the peroneus longus. The head is spherical, articulating 
with the first phalanx in front, and below with the sesamoid bones. 

Second. Is the longest. Its base articulates with the middle 
cuneiform, on the inside with the internal cuneiform, and on the 
outside with the third metatarsal and external cuneiform. 

Third. Is distinguished by the external surface of its base having 
two articular facets for the fourth metatarsal. The base articulates 
with the external cuneiform. 



LIGAMENTS. 49 

Fourth. Its base articulates with the cuboid, and on either side 
with the contiguous metatarsal bone. The internal lateral face of 
the bone is* distinguished by having two articular marks. 

Fifth. Is the smallest and readily recognised by the large tubercle 
projecting backwards and outwards from the base, into the superior 
part of which is inserted the peroneus tertius, and into the extremity 
the peroneus brevis. This process is a surgical guide in Hey's am- 
putation of the foot. The base articulates with the cuboid and 
fourth metatarsal. 

TOES. 

There are five on each foot. Each consists of three phalanges, 
with the exception of the first or great toe, which, like the thumb, 
has but two. 10 11 

The first row 12 of phalanges are smaller than those of the fingers, 
and readily distinguished by the narrowness of their bodies. The 
bases have a single concavity ; the anterior extremities have two 
convexities, separated by a groove. 

The second roiv. i3 — These phalanges have hardly any body ; the 
posterior extremities have two concavities separated by a ridge ; and 
the anterior, two convexities separated by a groove. 

The third row. 1 * — These phalanges are very small; their bases 
have two concavities and a ridge. The anterior extremity is flat 
and rough. 

Sesamoid Bones. — These are four small sections of a sphere of 
bone j two being imbedded in the tendon of the flexor brevis pollicis 
of each foot. The flat surfaces play on the inferior part of the head 
of the metatarsal bone of the great toe. 



SECTION II. 

ARTICULATIONS. 

LIGAMENTS. 

An articulation or joint is the connexion of one bone with an- 
other. Where much motion is required, it is necessary that carti- 
lage, ligaments, and synovial membranes should be employed in the 
mechanism. 

Cartilage. — Is white, flexible, elastic, and hard. Its chemical 
composition is, gelatine 44-5; water 55; phosphate of lime 0-5. 
By boiling it becomes yellow, swells, and the gelatine is dissolved. 
It resists mortification and putrefaction longer than any tissue ex- 
cept bone. When dried it becomes hard and contracted, and semi- 
transparent, resembling common glue. Soaking in water restores 
its appearance. It contains no red blood-vessels, nor can nerves 

5 



50 LIGAMENTS. 

or lymphatics be traced in it. Microscopically examined it ex- 
hibits OYal cells. Old age disposes it to ossify, particularly in the 
ribs and larynx. 

Perichondrium is the fibrous investing membrane of cartilage, 
corresponding to the periosteum of bone. 

Articular cartilages. — These coyer the extremities of bone and 
obviate or equalize pressure. Those lining the cavity are thicker 
on the edges; those covering a convexity are thicker in the middle. 
Inter-articular cartilages are free and moveable in the joint, not 
covering a bony surface, and held in their places by connexion with 
ligaments : they are called menisci, from their shape. 

Fibro-cartilage. — Is stronger and tougher than cartilage; it is 
composed partly of ligament and partly of cartilage ; it is found in 
the ear, at the symphysis pubis, and between the vertebrae. 

Ligaments consist of fibrous tissue, of which there are two kinds, 
white, which is inelastic, and yelloic, which is elastic ; the white is 
found in tendons, fasciae, and in most of the ligaments ; the yellow is 
• found in the ligamentum nuchas, and in many vessels and ducts. 
Ligaments are called capsular when they are bag-like, as at the 
shoulder and hip ; funicular, when cord-like, and membranous when 
like a riband. 

Synovial membranes are thin, transparent, closed serous B 
lining capsular ligaments, and secreting an albuminous fluid called 
synovia, which resembles in appearance the white of an egg. It 
lubricates the joints, and prevents attrition. Masses of fat outside 
of the synovial membranes are usually called glands of Havers. 
They do not secrete, however, but serve a mechanical purpose in 
filling up spaces which would otherwise be formed in many articula- 
tions during the performance of certain movements. The synovial 
fringes are nothing but folds of the synovial membrane, including 
small portions of fat. 

The principal kinds of articulations are termed : 
Synarthrosis, implying immobility, and including 
Sutura. — Bones of the skull. 
Harmonia. — Superior maxillary bones. 
Schindylesis. — Yomer with processus azygos. 
Gomjyhosis. — Teeth with alveoli. 
Ampeiartkrosis implies partial motion, and is exemplified in 
the symphyses, and in the bodies of vertebrae. 

Diarthrosis is a moveable articulation, and includes 

Arthrodia. — Such connexions as exist between the tarsal 

and carpal bones. 
Ginglymus. — Hinge-like joints, such as the elbow and 

ankle. 
Enarthrodia. — Ball-and-socket j oints, such as the hip and 
shoulder. 



ARTICULATION OF THE LOWER JAW. 



51 



ARTICULATION OF THE LOWER JAW. 

Capsular Ligament. — Extends from the border of the glenoid 
cavity of the temporal bone, and 

surrounds the neck of the condy- Fig. 30. 

loid process of the lower jaw. 

External Lateral Ligament. 5 
— Is broad and triangular, cover- 
ing the outside of the joint, ex- 
tending from the tubercle at the 
root of the zygoma to the outside 
of the neck of the condyle. (Fig. 
30.) 

Internal Lateral Ligament. — 
Properly speaking, not a ligament 
bu*t a fibrous band or sheath for 
the protection of vessels and nerves 

from the contraction of the pterygoid muscles. It passes from the 
spinous process of the sphenoid to the spine at the margin of the 
posterior mental foramen. 4 (Fig. 31.) 

Stylo- Maxillary, Q (Fig. 31,) is an extremely thin fibrous band, 
extending from the styloid process of the temporal bone to the 
angle of the lower jaw. 




Fig. 31. 



Fig. 32. 




Internal Articular Cartilage* is a thin oval plate, dividing the 
joint into two cavities. It is partly concave above and below, thick 
at the edges. (Fig. 32.) 

The Two Synovial Membranes.* 5 (Fig. 32.) One is reflected 
between the glenoid cavity and the interarticular cartilage ; the 
other between the cartilage and the condyle of the jaw. When the 
cartilage is perforate, the two cavities are lined by one synovial 
membrane. 



52 LIGAMENTS OP THE VERTEBRJE. 

LIGAMENTS OF THE VERTEBRA. 

BODIES. 

Intervertebral Substance. — The bodies of the vertebrae are united 
by fibrocartilaginous disks, which are twenty-three in number, con- 
sisting of concentric rings; toward the centre there is a yellow jelly- 
like mass, in a state of compression ; it is whiter and more abun- 
dant in infancy. On this account persons are stiffer in old age, and 
are shorter in the evening than they are in the morning. 

Anterior Vertebral Ligament 1 is in front of the bodies of the 
vertebrae (Fig. 35 1 ); extending from the second vertebrae of the 
neck to the first of the sacrum ; it is thin and gradually increases in 
breadth. 

Posterior Vertebral Ligament. — It lies upon the posterior surface 
of the bodies of the vertebrae, and extends from the occiput to the 
os coccygisj it is narrow and thick in the thorax, adheres closely* to 
the intervertebral substance, and its edges present a serrated 
appearance. 

Processes. — Oblique. — These are surrounded by capsular liga- 
ment, lined by a synovial membrane. 

Spinous. — The spaces between the processes are filled by the 
inter-spinal ligaments. In the back they are triangular, in the 
loins quadrangular, and in the neck deficient. The free edge of the 
ligament is thick and cord-like. 

Ligamentum Nuchse. — Continuation of the last, reaching from 
the seventh cervical vertebra to the vertical ridge on the occiput. 

Yelloio Ligaments are between the bony bridges of the vertebrae 
— twenty-three pairs ; the first is between the second and third 
vertebrae. They are remarkable for their elasticity and colour. 

ATLAS AND OCCIPUT. 

Anterior Ligament, is a strong, broad ligament, extending from 
the superior edge of the anterior arch of the atlas to the basilar pro- 
cess of the occiput. The middle portion is thick, and connected 
with the tubercle of the atlas. 

Posterior Ligament, is thin, broad, and loose, extending from the 
posterior arch of the atlas to the corresponding edge of the foramen 
magnum occipitis. It is perforated by the vertebral artery. 

Capsular Ligament, surrounds the superior oblique process of the 
atlas and the condyloid process of the occiput. Thicker and stronger 
in front. 

ATLAS AND DENTATA. 

Transverse Ligament, stretches across the atlas from one tubercle 






LIGAMENTS OF THE PELVIS. 



53 



Fig. 33. 



to the other, dividing it into two 
rings 2 (Fig. 33), and has an ap- 
pendix above, 3 connecting it with 
the occiput, and one below, 4 con- 
necting it with the dentata. 

Moderator Ligaments are short 
and thick; extending from the 
sides of the apex of the processus 
dentatus 5 to a process on the 
inner side of each condyle. They 
limit rotation of the head. 

Middle or Straight Ligament, 
reaches from the tip of the pro- 
cessus dentatus to the anterior edge of the foramen magnum. 

Capsular Ligament of the oblique process of the atlas and den- 
tata is very loose. 

Lacerti Ligamentosi are ligamentous bands extending from the 
occiput to the posterior part of the body of the dentata. 




LIGAMENTS OF THE PELVIS. 

Sacro-Iliac Symphysis. — The articular surfaces are covered by 
cartilage and united by short, thick, strong fibres, which are with 
difficulty divided. A yellow fluid is sometimes interposed, and in 
children and pregnant women a synovial membrane. 

Sacro-Iliac Ligament; short ligamentous fibres passing from 
bone to bone surrounding 

the joint, and thicker be- Fig- 34. 

hind. 

Sacro - Sp>inous Liga- 
ment; consists of two la- 
minae, composed of nume- 
rous strong fibres, passing 
from the posterior inferior 
spinous process to the trans- 
verse processes of the third 
and fourth sacral vertebrae. 
Greater Sacro- Sciatic Li- 
gament, 2 extends from the 
posterior inferior spinous 
process of the ilium, margin 
of the sacrum and of the 
first bone of the coccyx, to 
the inner margin of the 
tuberosity and ramus of the 
ischium. 

Lesser Sacro- Sciatic Ligament ; in front of last; arises from the 

5* 




54 



YEETEBR-E WITH THE BIB: 



side of the sacrum 3 (Fig. 34), and coccyx ; inserted into the spine 
of the ischium. 

These two ligaments form the 
Hz. IS posterior and lateral boundaries 

of the pelvis, converting the 
sacro-sciatic notch into two fora- 
mina 45 (Fig. 34). 

Ilio-Lv. m barL iga m en t. passes 
from the transverse process of 
the last lumbar vertebra to the 
• : ^terior part of the crest of the 
ilium. 3 (Fig. 35.) 

Lumbc - Sacral Ligament, 
arise- from the transverse pro- 
cess of last lumbar vertebra, and 
is inserted into the upper part 
of the sacrum. 2 (Fig. 35.) 

A :: . - Z merit. 

— Its fibres are indistinct, often 
wanting — runs in front of the 
whole length of coccyx from the 
last bone of the sacrum. 
P \ ; ;• ' L ' : : : :. arises from the inferior margin of 

the sacral canal, and terminates at the second bone of the coccyx. 

lie _Z ■ Kg. 35 . — Fills up the thyroid foramen; 

is membranous and thin, perforated at its upper part for the trans- 
mission of the obturator vessels. 

Smb-Fubk Ligament. — A thick, triangular ligament, rounding 
the apex of the arch of the pubis ; reaching from one bone to the 
other. 

S vpkysh Pi's. — Thr bones are connected by fibro-cartilage, 
: Tumbling intervertebral substance: sometimes there is a synovial 
membrane. A few transverse fibres in front and behind are called 
anterior and posterior ligaments. 




THORAX. 



r::::::.. 



z z ?. : i - . 



Ante Radiated Ligament. — Short fibres radiating from 

the head of the rib, to the two contiguous vertebras and the sub- 
stance between them. 

psular Ligament. — Surrounds the head of the rib; thickest 

)ve and below. 

LnMer-arHctdar Ligament. — A thin band passing from the ridge 
on the head of a rib to the intervertebral substance, dividing the 
cavity into tw( : h of which has a distinct synovial membrane. 

The Brat, eleventh, and twelfth are exceptions to this rule. 



UPPER EXTREMITY. 



55 




The tubercle of the rib is connected 
to the transverse processes by a capsu- 
lar ligament, and also the internal costo- 
transverse ligament* passes from the 
inferior edge of the transverse process, 
and is inserted in the sharp edge of the 
neck of the rib below. 

External costo-transverse Ligament.* 
— Is quadrangular, extending between 
the transverse process and the con- 
tiguous rib. 

Middle costo-transverse Ligament. — 
A collection of short irregular fibres 
mixed with reddish adipose tissue, 
passing directly from the transverse 
process to the rib. 

RIB WITH STERNUM. 

Anterior extremity of ribs. 

Anterior radiated Ligament 5 (Fig. 37). — Consists of a number of 
fibres, reaching from the cartilage of the true ribs to the sternum, 
and blending themselves with the periosteum. 

Posterior radiated Ligament. — Not so distinct as the last, passing 
in the same direction upon the under surface. 

Costo-xiphoid Ligament. — Reaches from the cartilages of the 
sixth and seventh ribs, to the ensiform cartilage. 

A synovial membrane and ligamentous fibres are found between 
the sixth and seventh, and eighth and ninth, sometimes. 

UPPER, EXTREMITY. 

SHOULDER. 

The clavicle and sternum have interposed a wedge-shaped inter- 
articular cartilage, dividing the joint into cavities, and the whole is 
surrounded by a strong capsular ligament 1 (Fig. 37), which is 
fibrous and thick, looser before 



than it is behind. 

Inter-clavicular Ligament. 2 — 
A ligamentous cord stretching 
from the end of one clavicle to 
the other. 

Rhomboid Ligament. 2 — A 
strong, thick ligament, proceed- 
ing from the upper surface of 
the cartilage of the first rib 
obliquely upwards and outwards 
to the inferior and sternal end 
of the clavicle. 



Fig. 37. 




o(3 



HUMERUS AND SCAPULA. 



CLAVICLE AND SCAPULA. 

Capsular Ligament.* — Surrounds the acromion process of the 
scapula, and the external extremity of the clavicle. The fibres 
upon the upper and lower surface are very distinct and strong. 

Coraco-clavicular Ligament 2 (Fig. 38). — Consists of two parts, 
one of which is called conoid; it is triangular and vertical; com- 
mencing at the root of the coracoid process, it expands as it ascends, 
and is fastened to the tubercle at the inferior extremity of the 
clavicle. The other is called trapezoid; it is in front of the last, 
arises at the internal edge of the coracoid process, and proceeds 
obliquely upwards to a ridge on the lower surface of the external 
end of the clavicle. 

Bifid Ligament. — Is an aponeurotic expansion, commencing at 
the coracoid process, terminating upon the inferior surface of the 
clavicle, and also upon the cartilage of the first rib. It protects the 
inferior portion of the subclavius muscle. 

Coraco-acromial Ligament (Fig. 38). — Is thick and triangular; 
the base commences upon the outer edge of the coracoid process, 
and the apex is fastened to the acromion ; it prevents a dislocation 
of the humerus upwards. 

Coracoid Ligament* (Fig. 38). — Is a small transverse fasciculus, 
stretched across the coracoid notch, and converting it into a foramen 
for the supra-scapular artery and nerve. 



U3IERUS AND SCAPULA. 



Fig. 38. 



Capsular Ligament 5 (Fig. 36). — 
Surrounds the glenoid cavity and the 
neck of the humerus ; it is loose and 
perforated by the tendon of the long 
bead of the biceps. 7 It is deficient 
behind; this deficiency is supplied 
by the tendons of the surrounding 
muscles, particularly the sub-scapu- 
laris. 

Coraco-humercd Ligament. 6 — Is 
sometimes called adscititium; is a 
thick fasciculus of the capsular liga- 
ment, proceeding from the coracoid 
process. It holds the head of the 
bone on a level with the glenoid 
cavity. 

Glenoid Ligament. — A prismatie 
ring of fibro-cartilage, attached to the 
edge of the glenoid cavity, and in- 
creasing its depth. The synovial membrane is very extensive, and 
communicates with the bursse of tendons. 




ELBOW JOINT. 



57 



ELBOW JOINT. 

Capsular Ligament. — It surrounds the extremities of the hume- 
rus, radius^ and ulna. It is strengthened by the 

Internal lateral Ligament 2 (Fig. 39), which, commencing at the 
internal condyle, has two insertions, one into the coronoid, and the 
other into the olecranon process of the ulna. 

External lateral Ligament* (Fig. 40). — Is triangular, com- 
mencing at the external condyle, and terminating in the annular 
ligament. 

Coronary or annular Ligament 5 (Fig. 41). — Is strong and dense, 
surrounding three-fourths of the head of the radius ; its extremities 
are fastened on either side of the lesser sigmoid cavity. 

Interosseous Ligament 5 (Fig. 39). — Is a ligamentous membrane, 
filling up the space between the radius and ulna throughout their 
length. It is perforated at its upper part, for the transmission of 
the posterior interosseal artery ; this deficiency is compensated for 
by the ligamentum teres* (Fig. 39), whose fibres are oblique and 
in an opposite direction to those of the interosseous ligament. It 
commences at the coronoid process, and terminates below the tubercle 
of the radius. 



Fig. 39. 



Fig. 40. 



Fig. 41. 






Sacciform Ligament. — Is a loose capsular ligament, surrounding 
the lower extremity of the ulna, and attached to the lesser sigmoid 



58 



FINGER JOINTS. 



cavity of the radius. This is strengthened by the anterior radio- 
ulnar ligament* (Fig. 42), which passes obliquely between the two 
bones, and the posterior radio-ulnar ligament. 

WRIST JOINT. 

This joint is formed by the greater sigmoid cavity of the radius 
and the scaphoid, semilunar, and cuneiform bones. It is surrounded 
by the capsular ligament, which is strengthened by an anterior 
ligament? (Fig. 42), a broad membranous layer ; an internal lateral 
ligament,* reaching from the styloid process of the ulna to the 
cuneiform and pisiform bone ; an external lateral ligament* reach- 
ing from the styloid process of the radius to the scaphoid bone ; 
and & posterior ligament, which is thin and loose, passing between 
the posterior surface of the radius, semilunar, and cuneiform bones. 



Fig. 42. 



Fig. 43. 





The carpal bones are held together by 
dorsal and palmar ligaments. The pisi- 
form hone has a distinct capsular liga- 
ment. The arrangement of the synovial 
membrane is represented by Fig. 43. 
The bases of the metacarpal bones are 
secured to the second row of the carpal bones by fibrous bands 
called dorsal and palmar ligaments. That of the thumb has a true 
capsular ligament. 

FINGER JOINTS. 

The joint between the metacarpal bones and the first row of pha- 
langes, is a ball-and-socket joint. It is secured by an internal and 
external lateral ligament 13 (Fig. 42), which are very thick in pro- 



KNEE JOINT. 



59 



portion to the size of the bone ; the anterior or palmar ligament 12 
is in front, and has the flexor tendons playing over it; the extensor 
tendon taking the place of a posterior ligament. The heads of the 
metacarpal bones are also connected by transverse ligaments. 14 

The second and third joints of the finger 16 are arranged upon the 
same principle as the first, with the exception of the transverse 
ligament. 

LOWER EXTREMITY. 

HIP JOINT. 

Capsular Ligament 9 (Fig. 35). — Is the largest and strongest cap- 
sule in the body, and surrounds the acetabulum and the neck of the 
femur. It is thicker and longer in front than it is behind, and is 
strengthened by a bundle of fibres, 9 called ilio-femoral. 

Cotyloid Ligament* (Fig. 34). — Is a thick prismatic ring of fibro- 
cartilage, surrounding and deepening the acetabulum. 

Ligamentum teres 7 (Fig. 34). — Is attached to a pit upon the head 
of the femur, and divides into two fasciculi, which are inserted into 
the corners of the notch of the acetabulum and the cotyloid ligament. 
The synovial membrane is extensive, and the Haversian mass is 
large. 



KNEE JOINT. 

This joint is surrounded by an expansion of the fascia lata of the 
thigh, called the involucrum generate. 

Anterior Ligament. — Is the ligament of the patella* (Fig. 44) ) 
it is the strongest ligament of the body. It is a continuation of the 
tendon of the quadriceps 

muscle, 1 in which the Fig. 44. Fig. 45. 

patella 3 is enclosed, pre- 
vious to its insertion into 
the tubercle of the tibia. 

Posterior Ligament. 
— Is the ligament of 
Winslow' (Fig. 45). It 
is a broad ligament pass- 
ing obliquely from the 
external condyle of the 
femur to the posterior 
part of the internal tube- 
rosity of the tibia. Its 
strongest fasciculi are 
derived from the semi- 
membranosus tendon. 3 
It has numerous openings for blood-vessels. 

Internal Lateral Ligament. — Is broad, 





thin, and membranous, 



60 



KNEE JOINT. 



Fig. 46. 



extending from the internal condyle of the femur to the lower part 
of the internal tuberosity of the tibia. 5 . 

External lateral Ligament. — Is a strong cord-like ligament 6 reach- 
ing from the external condyle to the superior extremity of the 
fibula. Posterior to this, and parallel with it, is another shorter 
ligament also connecting the femur and fibula. 

Semilunar Cartilages. — Are two prismatic rings of fibro-carti- 
lage, deepening the articular surfaces of the tibia. The external 7 
(Fig. 46) is the smaller and more circular. The internal 6 is the 
larger and a semicircle. The extremities are attached to the spi- 
nous process of the tibia. A small transverse ligament 4 connects 
them behind. 

Crucial Ligaments. — These cross each other. The anterior 2 
(Fig. 46), arises from a roughness in front of 
the spine of the tibia, and is inserted into the 
posterior part of the internal face of the ex- 
ternal condyle. The posterior* commences 
at a roughness behind the spine of the tibia, 
and is inserted at the anterior part of the 
external face of the internal condyle of the 
femur. 

The synovial membrane is the most exten- 
sive in the skeleton ; it forms folds in the in- 
terior of the joint, one of which is called the 
ligamentum mucosum, 5 which is triangular in 
shape, passing from the condyloid notch to 
a mass of fat in front of the tibia. The alar 
ligamennts are fringed folds of the synovial 
membrane, containing masses of fat on each 
side of the patella. 
The tibia and fibula are connected above by the 
Anterior Superior Ligament 1 (Fig. 44). — A short, strong liga- 
ment, extending obliquely between the heads of the two bones in 
front. 

Posterior Superior Ligament^ (Fig. 45). — Passes obliquely be- 
tween the heads of the two bones behind. The synovial membrane 
of this articulation is generally distinct from that of the knee-joint. 
Interosseous Ligament 11 (Fig. 46). — Is stretched between the 
tibia and fibula throughout their entire length, and an opening at its 
upper part transmits the anterior tibial artery. 

Anterior Inferior Ligament (Fig. 48). — Is a broad band passing 
obliquely between the two bones in front, and at their lower extre- 
mity. 

Posterior Inferior Ligament. — Is somewhat similar, passing ob- 
liquely between the lower extremities of the two bones. Besides 
these, the tibia and fibula are united by short strong fibres, passing 
from the contiguous surfaces of the two bones. 




ARTICULATIONS OP THE FOOT. 



61 



ANKLE JOINT. 



It is the most perfect hinge in the body. 

Internal Lateral or Deltoid Ligament* (Fig. 47). — Is triangular; 
its apex is attached to the internal malleolus, and its base to the 
os calcis, astragalus and calcaneo-scaphoid ligament. The tibialis 
posticis runs in a trochlea upon it. 

External Lateral Ligament* 7 8 (Fig. 48). — Consists of three 
parts, which arise from the external malleolus ; the anterior passes 
forwards, and is inserted into the astragalus \ the middle descends, 
and is inserted into the os calcis ; the posterior passes backwards, 
and is fastened to the astragalus. The synovial membrane is large 
and loose, and is reflected upon some condensed cellular tissue in 
front, which is sometimes called the anterior ligament. 



Fig. 47. 



Fig. 48. 





ARTICULATIONS OF THE FOOT. 

The astragalus and os calcis are united by a strong, thick, inter- 
osseous ligament, passing from the groove on the upper surface of 
the os calcis to the corresponding one of the astragalus. — Poste- 
riorly there is a short ligament, called the posterior ligament, upon 
which plays the tendon of the flexor longus pollicis muscle. 

The os calcis and scaphoid are united by the superior calcaneo- 
scaphoid ligament, which passes from the inside of the greater apo- 
physis of the os calcis to the outside of the scaphoid ; and by the 
inferior calcaneo-scaphoid, which occupies the triangular interval 
between the lesser apophysis of the os calcis and the tubercle of the 
scaphoid. Upon this rests a portion of the head of the astragalus. 

The os calcis and cuboid are united by the superior calcaneo- 
cuboid ligament, which is a very thin flat band of fibres extending 
directly forwards from the os calcis to the cuboid, and by the inferior 
calcaneo-cuboid, which consists of two planes of fibres, of which the 
superficial or inferior layer is a strong band of pearly-white fibres, 

6 



62 TEETH. 

extending from all the under surface of the os calcis to the groove 
of the cuboid. The deeper-seated or superior layer, extends from 
the anterior tuberosity of the os calcis obliquely to the ridge of the 
cuboid. 

The astragalus and scaphoid are united by a thin semicircular 
ligament, consisting of parallel fibres, extending from the neck of 
the astragalus to the margin of the concavity of the scaphoid. 

Cuneiform Bones. — They are united to each other and the sca- 
phoid, by dorsal, plantar, and interosseal ligaments. 

The Bases of the Metatarsal Bones. — That of the first is united by 
a strong capsular ligament with the internal cuneiform bone, having 
a distinct synovial membrane. Those of the second and third are 
united with the middle and external cuneiform bone, by dorsal and 
plantar ligaments ; those of the fourth and fifth by dorsal and planter 
ligaments with the cuboid. 

The heads of the metatarsal bones are united to each other by a 
strong transverse ligament; and to the phalanges by two lateral, 
the plantar, and an expansion of the extensor tendon. 

The phalanges. — Their ligaments are arranged similarly to those 
of the hand, and consist of two lateral and one plantar. 

TEETH. 

The teeth are placed in the alveolar processes of the upper and 
lower jaw, and are the hardest portion of the human body. The 
permanent teeth are thirty-two in number, sixteen in each jaw; they 
are divisible into four classes. On each side of each jaw there are 
two incisors, one cuspid, two bi-cuspid, and three molars; each 
tooth consists of a body or crown, which is the part exposed above 
the gum; the neck, a narrow portion surrounded by the gum; and 
a root or fang which is contained within the alveolus. The roots 
are surrounded by a periosteum, and perforated at their extremities 
by a foramen for the transmission of an artery and nerve. 

Incisors. — Are next to the median line; their edge is bevelled, 
and in early life serrated; the root is single and conoidal; those of 
the upper jaw are larger than those of the lower jaw. 

Cuspid, or Canine. — Is next to incisors. Its body is conoidal, 
and it has the longest root. Those of the upper jaw are sometimes 
called eye-teeth, those of the lower jaw stomach-teeth. 

Bi-cuspid. — Are next in size to the molars. The body has two 
grinding points, of which the external is the larger. The root is 
sometimes bifid and grooved upon either side. The anterior is the 
smaller. 

Molars. — They have large quadrilateral bodies, with four or five 
grinding points. In the upper jaw they have three divergent roots, 



TEETH. 



63 



two of which are external, and one is internal. In the lower jaw 
they have but two roots, which are anterior and posterior. The 
third molaj or wisdom-tooth is smaller, and less perfectly developed 
than the other two, and does not appear until manhood. 



Fig. 49. 




Structure. — Each tooth has three textures, the ivory or dentine, 
the enamel, and the cementum. 

The ivory forms the largest portion of the body, neck, and root, 
and gives form to the tooth. It is of a dull white colour, and harder 
than bone. Although apparently very compact, nevertheless it 
consists of numerous fine tubes (dental tubuli), the average diameter 
of which is about ^jVo °f an inch. These tubes are larger at their 
commencement, which opens upon the pulp-cavity. They radiate 
in nearly parallel lines, and their finest ramifications sometimes termi- 
nate in minute cells or in loops. The tubular character is proven 
by the passage of ink and other fluids along them. The inter- 
tubular substance is translucent, and finely granular. 

Dentine consists of 28 parts of animal, and 72 parts of earthy 
matter. The principal components are gelatine and phosphate of 
lime. It contains neither blood vessels nor nerves. 

The enamel is the hardest portion; it encrusts the body; it is 
white, brittle, and semi-transparent, thicker upon the grinding sur- 
face, and terminates by a thin edge at the neck. Its structure con- 
sists of radiating hexagonal prisms of about T ^ of an inch in dia- 
meter : it possesses neither vessels nor nerves. It is composed of 
earthy matter almost entirely; so that the action of an acid leaves 
but a trace of the animal matter. 

The cementum or crusta petrosa forms a thin coating over the 
root of the tooth, from the apex to the enamel. It resembles bone 



64 



CELLULAR TISSUE. 



in structure, containing cells and canaliculi. It increases with the 
advance in age, making the teeth of old persons appear to project. 

A cavity exists in the body and fangs of the teeth, which is filled 
by a pulp, principally composed of an artery, vein, and nerve, 
which enter at the small orifice at the point. The pulp-cavity 
diminishes in adult life by the formation of cementum in its upper 
part, which prevents the exposure of the pulp even when the body 
is much worn away. 




An infant gum contains the rudiments of fifty-two teeth, in sepa- 
rate cavities; twenty of them appear between the sixth month and 
third year of age, and fall out between the sixth and twelfth year; 
they are therefore called the deciduous or milk teeth, of which 
there are two incisors, one cuspid, and two molars on either side of 
each jaw. The order of the irruption is irregular, but the average 
is as follows: at the seventh month, two middle incisors; ninth 
month, two lateral; twelfth month, first molar; eighteenth month, 
canine; twenty-fourth, two last molars. The teeth of the lower 
jaw precede those of the upper by a short interval. The original 
state of the tooth is a soft pulp contained in a sac, which pulp 
gradually becomes converted into dentine. The enamel is formed 
in the outer wall of the sac. The cementum is formed by the peri- 
osteum of the tooth, which is the remains of the old sac. 

INTEGUMENTS, ETC. 



CELLULAR TISSUE. 



The cellular or areolar tissue is that substance found so universally 
distributed throughout the body. It serves for the purpose of con- 
necting muscles and organs, and forming a protection, being par- 



SKIN. 65 

ticularly abundant beneath the skin. When parts are torn in a 
subject it is very distinct, and its characters can then be best ob- 
served. It will be found to be white in colour usually, and to con- 
sist of a number of cells which freely communicate, as is manifested 
in anasarca, emphysema, and ecchymosis. It is elastic and tough 
when fresh; when dried it is opaque and crisp; long boiling converts 
most of it into gelatine. Its toughness is due to one set of fibres, 
which are white, inelastic, and straight ; of such most ligaments are 
formed. Its elasticity is due to another set of fibres, which are 
yellow, elastic, and curling; of such the ligamentum nuchse and 
middle coat of arteries are composed. 

It is very vascular, though most of its vessels do not contain red 
blood in health, as may be seen in inflammation produced by the air 
or any other stimulus. Its moisture is due to serum. 



Fat is found in almost every part of the body, with the exception 
of the penis, ear, eyelid, and ball, interior of cranium, lungs, &c, &c, 
but in great abundance under the skin and around the serous mem- 
branes. It is of a yellowish colour, and in life is in a semi-fluid 
condition. It consists of three elements, stearine, margarine, and 
elaine, which are contained in vesicles aggregated in lobules, held 
together by areolar tissue. In women fat is more abundant ; and in 
infants it is upon the surface of the body, rather than in the cavities. 

It is of use in diminishing pressure upon the hands and feet ; re- 
tains heat, being a bad conductor, and assists in nutrition, as is 
manifested in hibernating animals. 

skin. 

The skin is an external covering and protection, as well as an 
organ of touch and excretion. Its colour and thickness vary in 
different persons and in different parts of the same person. At the 
orifices of cavities it is converted into mucous membranes. The 
largest wrinkles are produced by the contractions of muscles, and 
by the flexion of joints; others of an angular variety, owing to the 
contractile character of the skin, are seen upon the back of the 
hand ; the third variety is spiral. 

The skin is perforated by hairs and perspiratory ducts, and 
contains sebaceous glands; these are considered as appendages. 
The skin consists of two layers, the true skin, also called cutis vera 
or chorion, and the cuticle or epidermis. The cutis vera is the 
thicker and deeper of the two : it is white, and semi-transparent in all 
persons ; its internal or inferior surface is much blended with the 
subjacent cellular tissue, and contains a number of pits or depres- 
sions; the external surface has a number of conical projections 
called papillee tactus } h which are particularly numerous in those 

6* 



66 



NAILS. 



Fig. 51. 



parts where there is much motion. On the hands and feet they are 
arranged in spiral and semicircular rows, 
which occasion a similar wrinkle of the 
cuticle. They consist of an artery, vein 
and nerve ; the sensibility of a part is in 
ratio to their number. The skin itself 
is formed of condensed cellular tissue, 
the yellow fibrous element predominating 
where great elasticity is required, as in 
the armpit; the white element, where 
resistance is demanded, as in the sole of 
the foot. Between the interstices of 
these fibres pass innumerable vessels, 
ducts, &c, &c. It is thickened by pres- 
sure; boiling reduces it to gelatine; and 
tannin converts it into leather. 

The cuticle or epidermis 3 ' affords pro- 
tection to parts most exposed to pressure 
or friction; its thickness varies with the 
amount of pressure to which it is sub- 
jected, as is seen by the comparison of 
the hand of the artisan with that of a 
delicate female. It is not permeated by 
vessels or nerves, but consists of par- 
ticles arranged in different laminae; 
those that are deepest are granular, 
those of the next layer are more com- 
pressed, whilst those upon the surface 
are mere scales. These superficial scales, 
«mMM^WiJM.' which are horny, are constantly being 

shed, and new particles constantly sup- 
plied by the moist granules, which are 
below. The laminated condition makes 
it easy to divide into different layers, 
and the inferior layer was formerly 
called by a distinct name, rete mucosum; 
but it is nothing more than the deepest 
or most recently-formed part of the 
cuticle, in which are cells containing 

the colouring matter : this is very abundant in moles, freckles, and 

in the skin of negroes. 




The nails are modifications of the epidermis. Their appearance 
is too familiar to every one to demand description. That portion 
which is concealed is called the root; that which is free or projecting, 




HAIRS. 67 

the edge; that attached to the surface of the cutis is the body. The 
matrix is that portion of the cutis under the root and body, which 
produces the nail. The lunula is that crescentic, white portion of 
the matrix near the root, and is due to 
a different arrangement of the capilla- Fig. 52. 

ries in that part of the matrix. The 
nail firmly adheres to the matrix, and 
is moulded upon it like the epidermis 
in other situations. The epidermis or 
cuticle is continuous with the nail, and 
neither passes over or under it ) being 
essentially of the same structure. By 
maceration the epidermis and nail n n 
can readily be removed from the cutis 
vera. m m The border of the root of 
the nail is jagged, thin, and soft, and 
consists of newly-formed substance ; 
the deep surface of the body is also soft, and marked by longitudi- 
nal grooves corresponding to the papillary ridges on the surface of 
the matrix ; but the edge and superficial portion of the nail is com- 
posed of scales more dense and fibrous. 

HAIRS. 

Hairs are found on all parts of the surface, except the palms of 
the hands, and soles of the feet ; and vary in length, thickness, 
shape, and colour, according to situation, age, sex, or race. The 
shaft is that portion projecting beyond the surface ; the bulb is that 
extremity contained in a follicle of the skin. The cuticular lining 
of this follicle is continuous with the bulb itself, there being a gradual 
change in the scales, as they pass from the follicle into the hair- 
bulb j the hair itself grows from the bottom of the follicle, like the 
nail from the matrix, or the epidermis from the cutis. If the hair 
is to be coloured, pigment-granules are here also developed. 

The human hair is a rod, and not as commonly supposed, a tube. 
The scales in the axis, of the hair are softer, and not so closely con- 
densed as those of the surface, and thus they contain a larger 
amount of pigment in the interstices, which produces that dark ap- 
pearance which is mistaken for a tube ; this loose, porous structure 
in the middle, is sometimes called the medulla, and the condensed, 
fibrous exterior is termed the cortex ; the scales of which are im- 
bricated, that is, they overlap each other like the shingles of a roof. 
Where the hairs are large, and especially where they serve as tactile 
organs, there may be a papilla in the bottom of the follicle furnished 
with nerves and vessels, which projects into the bulb, as in the 
whiskers of a cat, and the quills of a porcupine; an approach to 
this papillary projection may be seen in some of the hairs of man, 
but their size is much overrated. 



SEBACEOUS GLANDS. 



The hairs maintain a vital, though not a vascular connexion with 
the body ; the moisture is partly due to the sebaceous glands, whose 
secretion passes through them by capillary attraction. Mental 
emotion has occasioned the hair to become white in a single night ; 
some account for this by a secretion of fluid acid which percolates 
the tissue of the hair, and chemically destroys the colour. Ordinary 
gray hair resembles other hair in every respect, save that of colour. 



SWEAT GLANDS. 



These are found in great number upon the inferior surface of the 
cutis vera generally. In the axilla they form a layer, an eighth of 
an inch thick, which is mammillated, and of a reddish colour. They 
are about the size of a pin's head, are soft, and often compressed 
and surrounded by a network of capillary blood-vessels. They are 
distinguishable from pellets of fat by their pink colour, and semi- 
transparent texture. When magnified, they are seen to consist of a 
solitary tube, intricately ravelled, one end of which is closed, and 
buried within the gland, and the other (Fig. 51), opens upon the 
skin. The duct consists of two portions : the dermic part winds 
tortuously through the true skin, and terminates in a funnel-shaped 
opening between the papillae tactus ; the epidermic portion com- 
mences at the lower part of the cuticle, at first very indistinctly and 
without any defined continuity of structure with the duct below, 
gradually assuming the spiral form, and having the scales of which 
its walls are composed arranged parallel with the axis of the pas- 
sage. — The secretion varies in odour in different portions of the 
body, and in different races. 



SEBACEOUS GLANDS. 



Fig. 53. 




The sebaceous glands 
are found in most parts 
of the skin, except in 
the palms and soles; 
they are most abundant 
on the scalp and face, 
especially about the 
nose. The orifices open 
into hair follicles, or 
upon the general sur- 
face. They consist of a 
duct, terminating in a 
blind, pouch-like extre- 
mity, lined by an epi- 
thelium, in the particles 
of which are included 
granules of sebaceous 
matter. The secretion 
is subservient for the 



MUSCLES. 



lubrication of the hair and the skin. There are generally found in 
their ducts, parasites, of which two specimens are given in b and c, 

Fig. 54. 




Fig. 53. These animals are found in almost every individual, espe- 
cially in those possessing a torpid skin; and they multiply in sickness. 
The ceruminous glands of the ear resemble the sebaceous glands. 



SECTION III. 
MUSCLES. 

Muscles are formed of that substance usually called flesh, which 
has a peculiar contractile power, producing motion ; they consist, 
independently of the cellular tissue, vessels, and nerves, which enter 
into their formation, of a special tissue. Those muscles which are 
excited by the will, such as those of locomotion, are called voluntary. 
Those which act independently of the will, such as those of the in- 
testines and uterus, are called involuntary. Voluntary muscle is 
composed of a number of bundles of fibres, called fasciculi or lacerti. 

The fibres are about ^i^ of an inch in diameter, and are crossed 
by regular transverse striae, which give rise to the term " striped," 
as applied to the voluntary muscles ; although there are some 
striped muscular fibres found in organs which are involuntary, as in 
the case of the heart, pharynx, and upper part of oesophagus. 

Each fibre consists of a number of filaments or fibrillae, included 
in a tubular sheath, formed of a tough, delicate, elastic membrane, 



70 



MUSCLES OF THE HEAD AMD NECK. 



called the sarcolemma. Each fibrilla consists of a number of 
quadrangular particles, arranged in a linear series, and called sar- 
coid dements. 

The blood-vessels pass in between the fasciculi, and terminate in 
a capillary network, which passes between the fibrillar 

The nerves also penetrate the fasciculi, and terminate in loops, 
which do not penetrate the sarcolemma of the fibres. 

Involuntary muscles consist of pale "unstriped" fibres, with the ex- 
ception of the heart and gullet. They are generally flattened, and 
it is doubtful whether they have a sarcolemma. They are much 
smaller than the striped fibres, being not more than -ojoq P art °f 
an inch in diameter. The chief constituent of muscle is fibrin. 

The red colour of muscles is not altogether dependent upon the 
capillary vessels, but upon a peculiarity of colouring matter united 
with them. 

Every muscle has a belly and two extremities; that which is 
fixed is called the origin or head; that which is moveable, the in- 
sertion. Those which surround orifices, are called sphincters. 

A tendon is formed of condensed white fibrous tissue, reaching 
from the end of a muscle to some structure which it is intended to 
move. 

For further description, see " Physiology. " 

MUSCLES OF THE HEAD AFD NECK. 

Oc<:ip>ito- frontalis. 1 2 3 — Has four beHies. 
Origin, from the superior semicircular ridges of the occiput. 
Insertion, into the superior margin of the orbicularis oculi, and 

corrugator supercilii, and into 






Fig. oo. 




the internal angular process of 
the os fronds and os nasi. Use ; 
it elevates the eyebrows, making 
transverse wrinkles. 

Compressor Saris. 6 — Origin, 
from the root of the ala nasi. 
Insertion, tendinously into its 
fellow on the dorsum of the 
nose, and into the lower part 
of the os nasi. Use; it either 
compresses or dilates the nostril. 

Orbicularis palpebrarum . 4 — 
This is a sphincter surrounding 
the orbits of the eyes. Origin, 
from the nasal process of the 
superior maxillary, the os un- 
guis, the internal angular pro- 
cess of the os fronds, and the 



MUSCLES OF THE HEAD AND NECK. 71 

internal palpebral ligament. Insertion, into the orbitar and nasal 
processes of the superior maxillary, and into the palpebral liga- 
ment. Us&; it closes the eyes. 

That portion of the muscle immediately covering the eyelids is 
called ciliaris. 

Corrugator supercilii. — A narrow, small, and pointed muscle, be- 
neath the occipito-frontalis. Origin : internal angular process of 
the os frontis. — Insertion, into the occipito-frontalis and orbicularis. 
Use; it makes vertical wrinkles of the forehead. 

Levator Labii superioris alseque Nasi. 8 — It lies on the side of 
the nose. Origin, from the nasal and orbitar processes of the su- 
perior maxillary bone. Insertion, into the upper lip and wing of 
the nose. Use; it elevates the wing and sides of the nose. 

Levator anguli Oris. 9 — Small and concealed by the last. Origin, 
from the superior maxillary bone, below the infra orbitar foramen. In- 
sertion: corner of the mouth. Use; elevates the angle of the mouth. 

Zygomaticus minor.™ — Origin, from the malar bone. Insertion, 
into the upper lip. Use; it raises the upper lip outwardly. 

Zygomaticus major. ," — Origin, from the malar bone, behind the 
last. Insertion, into the corner of the mouth. Use; it draws the 
mouth obliquely upwards and outwards. 

Depressor Labii superioris alseque Nasi. — Very much concealed. 
Origin, from the alveolar processes of the incisor and canine teeth. 
Insertion, into the wing of the nose and upper lip. Use; depresses 
the upper lip and wing of the nose. 

Depressor anguli oris. 13 — Origin, from the base of the lower jaw, 
on th# side of the chin. Insertion, into the corner of the mouth. 
Use; it draws the mouth downwards. 

Depressor Labii Inferior is. 12 — Origin, from the base of the lower 
jaw, beneath and in front of the last. Insertion, into the whole side 
of the lower lip. Use; it draws the lip downwards. 

Levator Mentis — Is much concealed, and best viewed from the 
inside of the lip. Origin, from the alveolar processes of the lateral 
incisor and canine teeth. Insertion, into the lower lip. Use; it 
elevates the lip. 

Buccinator. 18 — Origin, from the coronoid process of the lower 
jaw, from the tuber of the upper jaw, and alveolar processes of both 
jaws. Insertion, corner of the mouth and lips. Use; it draws the 
mouth backwards, and presses the food between the teeth. 

Orbicularis oris." 7 — Is a circular muscle surrounding the mouth, 
has neither bony origin nor insertion, but is much connected with 
other muscles of the mouth. 

Masseter. 15 16 — Origin, from the superior maxillary and malar 
bones, and also from the zygoma of the temporal bone. Insertion, 
into the angle and external surface of the lower jaw. Use; it draws 
the jaw upwards and backwards. It is very strong, and consists of 
two planes of fibres. 



72 



MUSCLES OF THE NECK. 



Temporalis. — Origin, from the temporal fascia, and sides of the 
temporal, frontal, and parietal bones. A few fibres also arise from 
the zygoma. Insertion, into the coronoid process of the lower jaw. 
Use ; it draws the jaw upwards. 

Pterygoideus externus.* — Origin, from the pterygoid, spinous and 



Fig. 56. 




temporal processes of the sphenoid, 
and from the tuber of the upper max- 
illary bone. Insertion, into the neck 
of the lower jaw. Use ; it draws the 
jaw forwards. 

Pterygoideus internus. 3 — Origin, 
from the internal pterygoid process, 
and pterygoid fossa of the sphenoid ; 
and from the Eustachian tube. In- 
sertion, into the internal surface of 
the angle of the jaw. Use; it draws 
the jaw upwards and inwards. 



MUSCLES OF THE NECK. 

Fasciae. — There are two fascise for the neck ; the superficial and deep. 

The superficial fascia is continuous with that which covers the 
whole body. It consists of two laniinse, between which are enclosed 
the platysma myoides muscle. 

The deep fascia is formed of more condensed cellular tissue, and 
extends from the ligamentum nuchas to the larynx in front, includ- 
ing between its laminae vessels of the neck. Below it is fastened 

to the sternum, clavi- 



Fig. 57. 




cles, and first ribs. 
A strong process of it 
exists between the 
styloid process of the 
temporal bone and the 
angle of the jaw, and 
is called the stylo- 
maxillary ligament. 
It forms a loop, which 
acts as a pulley to the 
omo-hyoid muscle, 
and thence is con- 
tinued down behind 
the subclavius muscle 
into the ligamentum 
bicorne, forming a 
portion of the boun- 
dary of the thorax. 
Platysma myoides. 



MUSCLES OF THE NECK. 73 

This is included between two laminae of the superficial fascia of the 
neck, is a broad, thin muscle, and not always well developed in man. 
Origin, frQm the condensed cellular tissue below the clavicle. In- 
sertion, into the muscles and integuments upon the side of the face 
and lower jaw. Use; it draws the skin of the neck and lower jaw 
downwards. 

Sterno-cleido-mastoideus, 11 forms the most prominent feature on 
the outside of the neck. Origin, from the upper part of the ster- 
num, and sternal end of the clavicle. Insertion, into the mastoid 
process of the temporal and into the superior semicircular ridge of 
the occipital bone. Use ; acting with its fellow, it draws the chin 
towards the breast. 

Sterno-hyoideus.^ — Origin, from the sternum, clavicle, and car- 
tilage of the first rib. Insertion, into the inferior edge of the os 
hyoides. Use ; it draws the hyoid bone towards the sternum. 

Sterno-thyroideus. 15 — Origin, from the sternum and cartilage of 
the first rib. Insertion, into the side of the thyroid cartilage. Use ; 
it draws the cartilage downwards. 

Thyreo-hyoideus. 16 — Origin, from the side of the thyroid carti- 
lage. Insertion, into the body and cornua of the os hyoides. Use; 
it approximates the hyoid bone and thyroid cartilage. 

Omo-hyoideus. 17 i8 — Origin, from the superior edge of the sca- 
pula, near the coracoid notch. Insertion, into the base of the hyoid 
bone. Use ; it draws the hyoid bone downwards. It is tendinous 
in its middle. 

Digastricus. 1 3 — Origin, from the fossa, behind the mastoid pro- 
cess of the temporal bone. Insertion, into the base of the lower 
jaw, at the side of the posterior mental tubercle ; its middle is ten- 
dinous, and perforates the stylo-hyoid muscle near its insertion. 
Use ; it elevates the hyoid bone, and opens the mouth, even when 
the lower jaw is fixed. 

Stylo-hyoideus. 3 4 — Origin, from the middle and inferior part of 
the styloid processes of the temporal bone : it is perforated by the 
digastricus. Insertion, into the junction of the body and cornua 
of the hyoid bone. Use ; it draws the hyoid bone upwards and 
backwards. 

Styh-glossus. 9 — Origin, from the upper and internal part of the 
styloid process. Insertion, into the side of the root of the tongue. 
Use ; it draws the tongue backwards. 

Stylo-pliaryngeus.' 10 — Origin, from the inner side of the styloid 
process near its root. Insertion, into the side of the pharynx, be- 
tween the superior and middle constrictor muscles. Use ; it raises 
and widens the pharynx. 

Mylo-hyoideus, 5 forms the floor of the mouth. Origin, from the 
mylo-hyoidean ridge of the inside of the lower jaw. Insertion, into 
a white tendinous line, between it and its fellow, and into the hyoid 

7 



74 



MUSCLES OF THE CHEST. 



Fig. 58. 



bone. Use ; it draws the hyoid bone upwards, and projects the 
tongue. 

Genio-hyoideus. 6 — Origin, from the posterior tubercle, inside of 
the chin. Insertion, into the body of the hyoid bone. Use; it 
draws it upwards and forwards. 

Longus-colli. 3 5 fi — Origin, from the bodies of the three superior 
dorsal vertebras, and the transverse processes of the five lower cer- 
vical. Insertion, into the bodies of 
all the cervical vertebras. Use ; it 
bends the neck forwards and to one 
side. 

Rectus capitis anticus major. 1 - — 
(See Fig. 58.) Origin, from the 
transverse processes of the third, 
fourth, and fifth cervical vertebras. 
Insertion, into the basilar or cunei- 
form process of the occiput. Use ; 
it bends the head forwards. 

Rectus capitis anticus minor.* — 
Origin, from the atlas near its trans- 
verse process. Insertion, into the 
basilar process of the occiput. Use; 
it bends the head forwards. 

Rectus capitis lateralis.™ — Ori- 
gin, from the transverse process of 
the atlas. Iisertion, between the 
condvle and iugular eminence of the 
occipital bone. Use; it draws the 
head to one side. 

Scalenus anticus. 2 — Origin, from 
the transverse processes of the fourth, fifth, and sixth cervical ver- 
tebras, tendinously. Insertion, into the upper surface of the first 
rib in front of the groove for the subclavian artery. Use; it bends 
the neck forwards, or raises the first rib. 

Scalenus meclius. 7 — Origin, from the transverse processes of all 
the cervical vertebras tendinously. Insertion, into the upper sur- 
face of the first rib, behind the groove for the artery. Use ; same 
as last. 

Scalenus posticus. 8 — Origin, from the transverse processes of the 
fifth and sixth cervical vertebras. Insertion, into the upper face of 
the second rib beyond the tubercle. Use; it bends the neck and 
raises the second rib. 

MUSCLES OF THE CHEST. 

Pectoralis major. — Forms the cushion of the chest. Origin, from 
the two upper bones of the sternum, the sternal two-thirds of the 




MUSCLES OF THE CHEST. 



75 



clavicle, the cartilages of the fifth and sixth ribs, and from the ten- 
don of the external oblique muscle. Insertion, into the outer edge 
of the bicipital groove of the humerus. Use ; it draws the arm in- 
wards and forwards. 

Pcctoralis minor. 6 — Origin, from the third, fourth, and fifth ribs. 
Insertion, into the inner face of the extremity of the coracoid pro- 
cess of the scapula. Use ; it draws the scapula inwards and down- 
wards. 

Fig. 59. 




JSuoclavius. 5 — Origin, from the cartilage of the first rib. Inser- 
tion, into the inferior face of. the clavicle. Use. It draws the cla- 
vicle downwards. 

Serratus magnus, or anticus. 4 — Origin, from the nine upper ribs, 
five of its heads interdigitating with the external oblique muscle. 
Insertion, into the whole length of the base of the scapula. Use. 
It draws the scapula forwards. 

Intercostales externi. 11 — There are eleven on each side. Origin, 
from the transverse process of the vertebra, and the inferior sharp 



76 MUSCLES OF THE ABDOMEN. 

edge of the rib. Insertion, into the superior rounded edge of the 
rib below. The fibres pass obliquely downwards and forwards. 

Intercostales internL — Also eleven on each side. Origin, from 
the inferior edge of the rib, and costal cartilages. Insertion, into 
the superior rounded edge of the rib below, the fibres passing down- 
wards and backwards. Use. To approximate the ribs. 

Triangularis sterni. — Situated on the inner wall of the front of 
the chest. Origin, from the ensiform cartilage, and second bone of 
the sternum. Insertion, into the third, fourth, fifth, and sixth ribs. 
Use. To depress the ribs. 

MUSCLES OF THE ABDOMEN. 

Beneath the skin of the abdomen is the fascia superficial is abdo- 
minis, a layer of condensed cellular substance, varying in thickness 
in different individuals, and containing more or less fat. Its lami- 
nated character admits of its being dissected into several layers. 
In the groin it encloses the lymphatic glands, and is traversed at its 
lower part by the arteria ad cutem abdominis; it is thickened over 
the symphysis pubis, and constitutes the mons veneris. 

Ooliquus externus. i2 — Origin, from the eight inferior ribs, the 
first head being covered by the pectoralis major; the five superior 
heads interdigitate with those of the serratus anticus, and the three 
inferior, with those of the latissimus dorsi. The fibres pass ob- 
liquely downwards and forwards. Insertion, into the whole length 
of the linea alba, tendinously; into the anterior half or two-thirds 
of the crest of the ilium, by muscular and tendinous fibres; and into 
the body and crest of the pubes, forming thereby Poupart's liga- 
ment. As the tendinous fibres approach the pubes, they split, 
forming a triangular opening called the external abdominal ring; 15 
through which passes in the male the spermatic cord, and in the 
female the round ligament of the uterus. The edges of this ring 
are called columns or pillars. — This ring is prevented from splitting 
still further, by some transverse tendinous fibres inserted into the 
crest of the pubis. 14 The external edge of that portion of the ten- 
don is called Gimbernat's ligament. (Fig. 59.) 

Use. — It compresses the viscera of the abdomen, and approxi- 
mates the pelvis and thorax. 

Obliquus interims. 18 — Origin, from the three inferior spinous 
processes of the lumbar vertebrae, and from all those of the sacrum, 
from the whole length of the middle lip of the crest of the ilium, 
and from the outer half of Poupart's ligament. Insertion, into the 
six inferior ribs, into the ensiform cartilage, into the whole length 
of the linea alba, and also tendinously into the pubes behind the 
external abdominal ring. At the linea semilunaris, the tendon 
splits into two laminae, which thereby form a sheath for the rectus 
muscle; in the lower third or fourth of the muscle, both lanrime, 
however, pass in front, and include between them the pyramidalis. 



INGUINAL HERNIA. 77 

Transversalis abdominis. — Is beneath the last. Origin, from 
the transverse processes of the last dorsal and four upper lumbar 
vertebrae, from the internal lip of the crest of the ilium, and from 
the external half of Poupart's ligament; it also arises from the 
cartilages of the six inferior ribs. Insertion, into the ensiform car- 
tilage, linea alba, and pubes, in common with the internal oblique 
tendon. A portion of this common tendinous insertion is also into 
the crest of the pubes immediately behind the external abdominal 
ring, and thus the weakness at this part of the abdomen is in some 
measure protected. 

Rectus abdominis. 15 — Origin, from the symphysis and body of 
the pubes. Insertion, into the ensiform cartilage, and into the 
cartilages of the fifth, sixth, and seventh ribs. This muscle gra- 
dually increases in breadth and has tendinous intersections called 
lineoe transversa, which are three or four in number. 

Pyramidalis. 11 — Is in front of the lower part of the rectus, and 
about three inches in length. Origin, from the body of the pubes. 
Insertion, into the linea alba. It is sometimes wanting. 

Cremaster. — This muscle forms a muscular sheath for the cord 
and upper part of the testicle ; before the descent of the testicle, it 
constitutes the inferior edge of the internal oblique and transversalis 
muscles, which are much blended at this part ; hence its origin may 
be said to be the muscular portion of the lower edge of these muscles, 
and that its insertion is into the conjoined tendon of these muscles. 

Fascia transversalis. — This fascia covers the abdomen, and lies un- 
der the muscles and in front of the peritoneum j it is continuous 
with the iliac fascia, which surrounds the posterior part of the peri- 
toneum, and with the pelvic fascia, which surrounds that portion of 
peritoneum in the cavity of the pelvis. It is thin and tough, and 
near the groin possesses great density. 

This fascia is an object of study, particularly on account of the 
internal abdominal ring being situated in it. This point is usually 
much misunderstood, partly from the use of the term ring, which 
gives rise to the idea that it is a hole or opening like the external 
ring, and partly from the variety and confusion of terms employed 
in its description. It may be said to be that portion of the fascia 
transversalis where it ceases to cover the abdomen and commences to 
cover the cord ; here it is very thin, and an artificial or false dis- 
section readily can form a ring or hole with a well-defined edge. 
But such does not exist in nature, for the fascia is continued from 
the abdomen upon the cord. 

INGUINAL HERNIA. 

Inguinal hernia is of two kinds ; oblique or indirect, and direct or 
ventro-inguinal hernia. Oblique is by far the most common ; and 

7* 



78 INGUINAL HERNIA. 

in order to understand the anatomy of it, it will be necessary to bear 
in mind the arrangement of the parts previous to the descent of the 
testicle, the subsequent and natural condition, and also the alteration 
of the parts by the hernial protrusion. 

Oblique inguinal hernia is a protrusion of intestine through a pas- 
sage originally made by the escape of the testicle from the loins to 
the scrotum ; and afterwards occupied by the spermatic cord. Until 
the seventh month of foetal life the testicle reposes in the lumbar 
region beneath the kidney, but not within the cavity of the perito- 
neum. As yet there is no spermatic cord formed, the constituents, 
to wit, the artery, vein, duct, &c, each approaching the testicle 
separately. About this period the testicle ordinarily descends, by 
means of the gubernaculum testis a contractile structure attached to 
its inferior extremity, and is enveloped in the scrotum. In its pas- 
sage it must come in contact with the various structures forming the 
parietes of the abdomen, viz., the peritoneum, fascia transversalis, 
the transversalis, internal and external oblique muscles, the super- 
ficial fascia, and the skin. Now each of these structures, with the 
exception of the external oblique muscle, will be found to form a 
covering for the testicle and cord, because it does not perforate them 
but pushes them before it ; although these coverings may be modi- 
fied in some degree, nevertheless there is a representation of every 
layer of the walls of the abdomen ; and this is the case not only in 
the coverings of the testicle and cord, but also in the coverings of 
a hernia protrusion ; hence, if a student understands the changes 
which take place in the descent of the testicle, he must necessarily 
understand the mode by which this kind of a hernial protrusion 
obtains its coverings. 

Here we must caution students from attaching too much impor- 
tance to words or terms used in description, for they vary with diffe- 
rent writers ; but let him keep constantly before his mind the thing 
itself, as if he were making a dissection ; for by actual dissection he 
can understand it thoroughly, although he may not know the name 
of a single part. 

Descent of the testicle — In the first place, by the contraction of 
the gubernaculum testis, the testicle is brought in contact with the 
peritoneum, and since it is not in the peritoneal cavity, it must 
necessarily push before it a doubled lamina of peritoneum. Thus 
the testicle gets a covering of serous membrane arranged as serous 
membranes always are ; that is, one lamina covers the testicle, and 
the other lines the cavity in which it is contained, and it is called 
the jperitestis or tunica vaginalis testis. The communication between 
the peritoneum and peritestis is afterwards obliterated, otherwise the 
bowel could readily pass down ; and when this obliteration does not 
occur, and the bowel does pass down, it constitutes a variety of her- 
nia, termed congenital. As the testicle descends, the spermatic artery, 



INGUINAL HERNIA. 



70 



vein, and vas deferens descend with it, and thus the cord is formed ; 
the components are held together by means of cellular tissue, the 
remains of>the canal of peritoneum, connecting the peritoneum and 
peritestis. Organs that have been of use in the system are never 
entirely absorbed, but converted into another, which serves a diffe- 
rent purpose — as in the case of an artery when tied for aneurism, it 
becomes a cord ; the umbilical vein becomes the ligamentum teres. 

Now, the next structure with which the testicle comes in contact, 
is the fascia transversalis j let us follow this in its descent with the 
testicle, and observe the changes which it undergoes. It is not per- 
forated as this (Fig. 60) and most pictures represent/ but pushed 
before the testicle, covering it and the cord. The point where this 
protrusion takes place, is midway between the anterior superior 
spinous process of the ilium and the pubes, and about an inch and 
a half above Poupart's ligament, and is called the internal abdo- 
minal ring ; but there is no hole or opening unless made with a 
scalpel. The fascia is continuous from the abdomen upon the cord, 
although that portion covering the abdomen is tougher and thicker 
than that of the cord. If the cord is stretched, this portion of the 
fascia will resemble a funnel, and hence some call it the infundibuli- 
forni fascia or internal spermatic fascia. That portion which 
covers the testicle, assists in forming its cellular coat, which is 
termed by some tunica vaginalis communis testis, by others, the 
fascia propria. 

Terms are matters of minor im- 
portance; the truth to be taught 
is, that the testicle, cord, and abdo- 
men are invested by the same fascise, 
having different names and different 
thicknesses in different parts. 

The next layer of the abdominal 
wall with which the testicle comes in 
contact is the transversalis muscle. 
At the lower part of the abdomen, the 
internal oblique is so much blended 
with the transversalis, that the two 
maybe considered as having the same 
relation to the testicle in its deseent, 
and also to hernia. At the internal 
abdominal ring, the testicle, already 
covered by the peritoneum and fascia 
transversalis, comes in contact with 
these muscles ; it does not perforate 
them, but pushes their conjoined 
lower edge before it, obtains for it- 
self and cord a muscular covering, 



Fig. 60. 




SO INGUINAL HERNIA. 

which is the cremaster muscle ; and this accounts for that looped 
appearance which the fibres of this muscle have upon the testicle ; 
also, for the muscle being thicker upon the anterior part of the cord. 
These muscular fibres are very pale, and very scattered upon the 
lower part of the testicle, and form an imperfect covering for the 
testicle. When the cremaster is cut away from the transversalis 
and internal oblique, their inferior edge presents an arched appear- 
ance. 

The tendon of the external oblique is the next structure opposing 
its descent, and since this is very tough, it is not pushed before the 
testicle ; but the testicle passes obliquely downwards and inwards 
for an inch and a half, until it gets opposite the external abdominal 
ring, which is a hole, and at which it emerges between its columns 
or pillars. The fact, that in health these two rings are not opposite 
contributes much to the strength of the arrangement, and prevents 
the more frequent occurrence of hernia, which is much favoured by 
a deficiency in the fibrous character of the tendon of the external 
oblique. 

The space between these two rings, is called the inguinal, abdo- 
minal, or spermatic canal. It is bounded anteriorly by the inferior 
edge of the internal oblique and transversalis muscles, the tendon of 
the external oblique, the superficial fascia, and skin ; posteriorly by 
the transversalis fascia, and the conjoined tendon of the transversalis 
and internal oblique muscles; inferiorly, by Poupart's ligament. 

When the hernia does not emerge from this canal, it is called a 
concealed inguinal hernia. 

At the external abdominal ring, the testicle, with its covering, 
comes in contact with the superficial fascia, which has already been 
described as consisting of numerous laminse, one of which can 
readily be shown to extend between the columns of the ring, and 
hence it is called the intercolumnar fascia, by some, by others, the 
external spermatic, &c. That portion of the fascia transversalis en- 
gaged in forming the cellular coat of the testicle, is actually blended 
with the superficial fascia of the testicle, on account of the inter- 
vening muscular structure, that of the cremaster being deficient in 
some parts, and very spare in others. 

The skin is, of course, readily traced from the abdomen to the 
scrotum, although in the scrotum it is modified by the dartos, which, 
according to some, is an expansion of the gubernaculum testis. 

We have seen the changes which take place in the descent of 
the testicle, and are now prepared to consider the escape of the in- 
testine. 

The convolution or knuckle of intestine first presses against the 
peritoneum, and being contained within the cavity, can only push 
before it a single lamina. This portion of the peritoneum always 



MUSCLES OP THE ABDOMEN. 81 

forms the hernial sac, which gradually increases in size and thickness. 
In this variety of -hernia (oblique inguinal), the protrusion takes 
place at the internal ring ; the sac must then necessarily be covered 
by the transversalis fascia and cremaster muscle, and after passing 
obliquely down the inguinal canal, it emerges at the external abdo- 
minal ring, where it receives an investment of superficial fascia and 
skin. 

That portion of the superficial fascia which fills up the external 
abdominal ring between its columns, and called intercolumnar, when 
pressed against by the protrusion is thickened and expanded. 

When a hernia exists, the connexion between this fascia and the 
edges of the external abdominal ring is so close that the tendon of 
the external oblique seems to be continued into the fascia; and 
some have therefore considered it as derived from the tendon, and 
not from the superficial fascia, as we have described; and indeed we 
frequently find, even when no hernia exists, a thin layer extending 
from the tendon of the external oblique to the spermatic cord. 

Hence, in the operation for hernia, the following layers are cut 
through : — 

Skill, superficial fascia, intercolumnar fascia, cremaster muscle, 
transversalis fascia, and the hernial sac. 

That portion of the fascia transversalis which covers the hernial 
sac is also thickened, and often called the infundihuliform fascia, 
or the internal spermatic fascia. 

In the dissection of a hernial sac, we will find alterations in thick- 
ness and colour, the consideration of which properly belongs to the 
surgical part of this work. 

Direct or ventro-inguinal hernia consists of a protrusion directly 
at the external abdominal ring, and of course it does not pass through 
the canal. The coverings are the shin, superficial fascia, interco- 
lumnar fascia, the common tendon of the internal oblique and 
transversalis muscles, transversalis fascia, and hernial sac. 

This variety is not of so frequent occurrence, on account of the 
insertion of the tendon of the internal oblique and transversalis into 
the pubes immediately behind the external abdominal ring,, which 
protects this opening, and therefore it must be ruptured or expanded 
when a protrusion takes place at this ring ; when it is ruptured, of 
course this covering of the sac does not exist. 



MUSCLES OF THE UPPER AND POSTERIOR PART OP THE ABDOMEN. 

Diaphragm. — This muscle forms the septum between the thorax 
and abdomen ; it consists of two parts, a greater and lesser muscle. 



82 



MUSCLES OF THE ABDOMEN. 



Fie. 61. 




The greater 123 muscle 
arises from the ensi- 
form cartilage, from 
the ligamentum ar- 
cuaturn, 5 which is a 
tense ligament pass- 
ing from the root of 
the transverse process 
of the first lumbar 
vertebra to the infe- 
rior part of the middle 
of the twelfth rib, and 
from six inferior ribs ; 
the fibres converge to 
the cordiform tendon, 
which is in the centre. 
Between its costal and 
ensiform origin there 
is a small triangular 
fissure filled up with 
fat, which sometimes 
leaves an opening for 
hernia. The lesser 810 muscle consists of two bellies, which are 
called crura, the right of which is the larger. Origin, from the 
second, third, and fourth lumbar vertebrae. Insertion, into the 
cordiform tendon. 

There are three openings in the diaphragm; one in the tendinous 
centre, 13 called foramen quadratum, which transmits the ascending 
vena cava ; another, an elliptical muscular opening, 12 called foramen 
otsophageum, through which passes the oesophagus, and the par 
vagum nerves; and the third, the hiatus aorticus, 11 which is between 
the crura, and in front of the vertebra ; through it pass the aorta, 
the thoracic duct, the azygos vein, and the great splanchnic nerve. 
Use ; it widens the thoracic, and diminishes the abdominal cavity. 

Quadratus Jumborum. — Origin, 15 from the crest of the ilium. 
Insertion, into the transverse processes of the last dorsal and all the 
lumbar vertebras, and also into the last rib beneath the ligamentum 
arcuatum. Use ; it bends the loins to one side. 

Psoas parvus. — Not always present. Origin, from the last dorsal 
and first lumbar vertebrae. Insertion, by a long tendon, into the 
crest of the pubes and fascia iliaca. 

Psoas magnus 1 * — Origin, from the transverse processes of all 
the lumbar vertebrae, and from the bodies of the four upper lumbar 
and last dorsal vertebrae. Insertion, into the lesser trochanter of 
the femur, and into one inch below it. 

Iliacu-s internus. — Origin, from the transverse process of the 



MUSCLES OF THE BACK. 



83 



last lumbar vertebra, from the costa and crest of the ilium, and from 
the capsule of the hip joint. Insertion, into the tendon of the psoas 
magnus. Use; the action of the last two muscles is the same, to 
bend the body forwards and draw the thigh upwards. 

MUSCLES OF THE BACK. 

Trapezius. 1 — Origin, from the superior semicircular ridge of the 
occiput, from all the spinous processes of the neck, by means of 
the ligamentum nuchae, and from all those of the back. Insertion, 
into the external third of the clavicle, into the acromion process, 
and spine of the scapula. Use ; it draws the scapula towards the 
spine. 

Fig. 62. 




Latissimus dor si.* — Origin, from the seven inferior spinous pro- 
cesses of the back, and from all those of the loins and sacrum, also 



84: MUSCLES OF THE BACK. 

from four inferior ribs, by heads which interdigitate with those of 
the external oblique. Insertion, by a thick flat tendon, in common 
with the teres major, into the posterior ridge of the bicipital groove. 
Use ; it draws the humerus downwards and backwards. 

Serratus posticus inferior 1Q — Origin, from the two inferior 
spinous processes of the back, and the three superior of the loins. 
Insertion, into the last four ribs. Use; it draws the ribs downwards. 

Bhomhoideus minor. 11 — Origin, from the three inferior spinous 
processes of the neck. Insertion, into the base of the scapula oppo- 
site the spine. 

Rhomboideus major. 12 — Origin, from the spinous processes of the 
last cervical, and of the four superior dorsal vertebras. Insertion, 
into the base of the scapula below the spine. Use; the last two 
draw the scapula upwards and backwards. 

Serratus posticus superior. — Origin, from the three inferior spi- 
nous processes of the neck, and the two superior of the back. In- 
sertion, into the second, third, fourth, and fifth ribs. Use; it draws 
the ribs upwards. 

Levator anguli scapulae. 10 — Origin, from the transverse pro- 
cesses of the three, four, or five superior cervical vertebrae. Inser- 
tion, into the angle of the scapula, and its base above the spine. 
Use ; it draws the scapula upwards. 

Splenius.' 13 14 — It consists of two parts; splenius capitis and sple- 
nius colli. Origin, from the spinous processes of the five inferior 
cervical and the four superior dorsal vertebrae. Insertion, into the 
occipital bone, between the two semicircular ridges, and into the trans- 
verse processes of the two superior cervical vertebrae. Use; draws 
the head and neck backwards. 

Sacro-lumbalis and longissimus clorsi. — These two muscles arise 
in common (Fig. 63.) Origin, from the spinous and transverse pro- 
cesses of the loins and sacrum, and from the crest of the ilium. 
The first 3 is on the outer side. Insertion, into the angles of the rib. 
The latter 3 is nearest the spine. Insertion, into all the transverse 
processes of the back except the first, and into all the ribs beyond 
their tubercles, except the last two. Use; to keep the spine erect, 
and draw down the ribs. 

Accessorii ad sacro-lumoalem. — Are muscular slips arising from 
the eight lower ribs and continued into the sacro-lumbalis. 

Spinalis dorsi.* — Origin, from the three inferior spinous pro- 
cesses of the back, and two superior of the loins. Insertion, into 
the nine superior spinous processes of the back, except the first. 
Use ; to keep the spine erect. 

Cervicalis descendens. 5 — Origin, from the four superior ribs. 
Insertion, into the fourth, fifth, and sixth transverse processes of 
the neck. 

Transversalis cervicis. 69 — Origin, from the five superior trans- 



MUSCLES OF THE BACK. 



85 



Insertion, into the five middle trans - 
Use; the two last draw the neck 



Fig. 63. 



verse processes of the back, 
verse processes of ^ the neck, 
back ward. % 

Trachelo-mastoid. 7 — Origin, from 
the three superior transverse processes 
of the back and from the five inferior 
transverse processes of the neck. In- 
sertion, into the mastoid process. 

Complexus. 8 — Origin, from the trans- 
verse processes of the four inferior cer- 
vical and seven superior dorsal, and 
from the spinous process of the first dor- 
sal vertebra. Insertion, into the occiput 
between its semicircular ridges. Use ; 
the two last draw the head backward. 

Semi-spinalis cervicis. 11 — Origin, 
from the six superior transverse pro- 
cesses of the back. Insertion, into the 
spinous processes of the five middle cer- 
vical vertebrae. 

Semi-spinalis dorsi. 10 — Origin, from 
the transverse processes of the seventh, 
eighth, ninth, and tenth dorsal ver- 
tebrae. Insertion, into the spinous pro- 
cesses of the two lower cervical, and 
five upper dorsal vertebrae. 

Multifidus spinae. 13 — Origin, from 
the posterior surface of the sacrum, and 
the back part of the ilium, and from 
the oblique and transverse processes of 
all the vertebrae of the loins and back, 
and of the four inferior of the neck. 
Insertion, into the spinous processes of 
all the vertebrse of the loins and back, 
and of the five inferior of the neck. Use ; the three last twist the 
spine when acting without their fellows. 

Rectus capitis posticus major. — Origin, from the spinous process 
of the dentata. Insertion, into the occiput at its superior semi- 
circular ridge, and below it. Use ; it turns the head. 

Rectus capitis posticus minor. — Origin, from the tubercle of the 
atlas. Insertion, into the occiput, at the inferior semicircular ridge, 
and below it. 

Obliquus superior. — Origin, from the transverse process of the 
atlas. Insertion, into the outer end of the inferior semicircular 
ridge of the occiput. 

Obliquus inferior. — Origin, from the spinous process of the den- 
tata. Insertion, into the transverse process of the atlas. 

8 




86 MUSCLES OF THE SHOULDER AND ARM. 

Inter spinales. — Between the spinous processes of all the vertebrae. 
In the neck, they are double : in the back, tendinous; in the loins, 
single and well-marked. 

Inter-transversarii. i8 — Between all the transverse processes. In 
the neck, double; in the back, tendinous; in the loins fleshy and 
single. Use. To approximate these processes. 

Levatores costarum. 17 — Origin, from the transverse processes of 
the last cervical and eleven upper dorsal vertebrae. Insertion, into 
the upper edge of the rib below, and sometimes into the second rib 
below. Use. To elevate the ribs. 

MUSCLES OF THE SHOULDER AND ARM. 
FASCIA. 

The brachial fascia covers the muscles of the upper extremity, 
commencing at the spine of the scapula and clavicle. Upon the 
deltoid it is thin. At the elbow it sends several processes to the 
bone, which serve for the origin of muscles, and in front it receives 
a portion of tendon from the biceps muscle, which renders it tense. 

At the wrist it forms the anterior and posterior annular liga- 
ments, which bind down the tendons of the hand, and in the hand 
it forms the palmar aponeurosis. 

Deltoid. 5 — Origin, from the spine of the scapula, its acromion 
process, and the external third of the clavicle. Insertion, into a 
triangular roughness near the middle of the outer side of the hume- 
rus. Use. It raises the humerus. (Fig. 62.) 

Supra-spinatus. 17 — Origin, from the whole of the fossa supra- 
spinata. Insertion, into the inner facet of the greater tuberosity of 
the humerus. Use. It raises the arm and turns it outwards. 

Infraspinatus. 1 * — Origin, from the whole of the fossa infra- 
spinata. Insertion, into the middle facet of the greater tuberosity 
of the humerus. Use. It rotates the humerus outwards and back- 
wards. 

Teres minor. ^ — Origin, from the lesser costa of the scapula. 
Insertion, into the outer facet of the greater tuberosity of the hume- 
rus. Use. It rotates the humerus outwards, and draws it down- 
wards and backwards. 

Teres major.™ — ^Origin, from the posterior surface of the inferior 
angle of the scapula, and a part of its lesser costa. Insertion, into 
the posterior edge of the bicipital groove of the humerus in common 
with the tendon of the latissimus dorsi. Use. It rotates the hume- 
rus inwards and draws it downwards and backwards. 

Subscapular is* (Fig. 64.) Origin, from the whole of the costa 
of the scapula. Insertion, into the lesser tuberosity of the humerus. 
Use. It rotates the humerus inwards, and draws it downwards. 

Biceps flexor cuhiti. 7 — Origin, from the superior extremity of the 



MUSCLES OF THE FORE-ARM. 



87 



Fig. 64. 



glenoid cavity, by a long tendon which passes through the joint 

and bicipital groove, and by a short head 

from the coracoid process of the scapula. 

Insertion , into the posterior and inferior 

parts of the tubercle of the radius, and 

into the brachial fascia. Use. It flexes the 

fore-arm. 

Coraco-bracJiialis. 6 — Origin, from the 
middle facet of the coracoid process of the 
scapula, in common with the short head of 
the biceps. Insertion, into the middle of 
the os humeri by a rough ridge on its in- 
ternal side. Use. It draws the arm up- 
wards and inwards. 

Bracliialis Interims. 9 — Origin, from the 
anterior and lower half of the os humeri. 
Insertion, in front of the base of the coro- 
noid process of the ulna. Use. It flexes 
the fore-arm. 

Triceps extensor cubiti. 10 — Origin, by 
three heads ; the first or longus, is from the 
inferior part of the glenoid cavity. The 
second or external, is from a ridge from the 
back part of the os humeri, just below its 
head ; and the third or brevis, is from the 
inner side of the os humeri, near the bici- 
pital groove. Insertion, into the olecranon process of the ulna. Use. 
It extends the fore-arm. 

Anconeus. 11 (Fig. 67.) — Origin, from the external condyle of the 
humerus. Insertion, into the outer side of the ulna below the ole- 
cranon. Use. It extends the fore-arm. 

MUSCLES OF THE FORE-ARM\ 

These are eighteen in number, eight of which are on the front of 
the arm, and are flexors j for the most part they arise from the inter- 
nal condyle. The remaining ten are extensors, and arise for the 
most part from the external condyle. 

Pronator radii teres. 41 (Fig. 65.) — Origin, from the internal con- 
dyle of the humerus, and the coronoid process of the ulna. Inser- 
tion, into the middle and external side of the radius. Use. It 
rotates the hand inwards. 

Flexor carpi radialis. 5 — Origin, from the internal condyle of the 
humerus, the brachial fascia, and the inter-muscular septa. Inser- 
tion, into the base of the metacarpal bone of the index finger. Use; 
it flexes the hand at the wrist. (Fig. 65.) 

Palmaris longus.® — Is sometimes deficient. Origin, from the 




88 



MUSCLES OF THE FORE-ARM. 



internal condyle. Insertion, into the annular ligament and palmar 
aponeurosis. Use ; it bends the hand. 



Fig. 65. 



Fig. 66. 





Flexor carpi ulnar is. 8 — Origin, from the internal condyle, from 
the ridge at the inner side of the ulna and from the olecranon. In- 
sertion, into the pisiform hone and into the base of the metacarpal 
bone of the little finger. Use; it flexes the hand. 

Flexor sublimis digitorum perforatus? — Origin, from the in- 
ternal condyle of the humerus, the coronoid process of the ulna, and 
the tubercle of the radius. Insertion, by four split tendons into the 
second phalanges of the fingers. Use; it bends the hand and 
fingers. 

Flexor profundus digitorum per for ans.* (Fig. 66.) — Origin, from 
the ulna by its anterior flat surface, from its coronoid process, and 
from the interosseous ligament. Insertion, by four tendons, which, 
passing through the perforations in the tendons of the flexor sub- 
limis, are inserted into the third phalanges of the fingers. 



MUSCLES OF THE FORE-ARM. 



89 



Flexor longus pollicis. 5 — Origin, from the internal condyle of the 
humerus, and the middle two-thirds of the radius, and a part of the 
interosseous ligament. Insertion, into the base of the second pha- 
lanx of the thumb. (Fig. QQ.} 

Pronator quadratics. 6 — Origin, from the Fig. 67. 

inner border and anterior surface of the 
ulna, near its lower extremity. Insertion, 
into the corresponding surface of the radius. 
Use ; it rotates the radius inwards. 

Supinator radii longus. 4 " (Fig. 67.) — 
Origin, from the ridge leading, to the ex- 
ternal condyle of the humerus. Insertion, 
into the radius just above its styloid pro- 
cess. Use; it rotates the radius outwards. 

Extensor carpi radialis longior. 5 — (Fig. 
67.) Origin, from the ridge of the external 
condyle of the humerus. Insertion, into 
the posterior part of the base of the meta- 
carpal bone of the forefinger. 

Extensor carpi radialis brevior. 6 — Ori- 
gin, from the external condyle of the hume- 
rus, and from the external lateral ligament. 
Insertion, into the posterior part of the base 
of the metacarpal bone of the middle finger. 

Extensor carpi ulnaris. 10 — Origin, from 
the external condyle and the brachial fascia. 
Insertion, into the base of the metacarpal 
bone of the little finger. Use; the last 
three extend the hand. 

Exteiiser digitorum communis. 8 — Origin, 
from the external condyle. Insertion, by 
four tendons which are connected by slips 
previous to their insertion into all the pha- 
langes of the fingers. Use; it extends the 
joints of the fingers. 

Supinator radii brevis. — Origin, from the external condyle, and 
from a ridge of the ulna on its posterior surface. Insertion, into 
the radius between its tubercle and the insertion of the pronator. 
Use; it rotates the radius outwards. 

Extensor ossis metacarpi pollicis manus. — Origin, from the 
posterior surface of the ulna, from the interosseous ligament, and a 
part of the radius. Insertion, into the base of the metacarpal bone 
of the thumb, and into the trapezium. 

Extensor minor pollicis manus. 13 — Origin, from the back of the 
ulna below its middle, and from the interosseous ligament. Inser- 
tion, into the first phalanx of the thumb. 

8* 




90 



MUSCLES OF THE HAND. 



Extensor major pollicis manws. 14 — Origin, from the back of the 
ulna above its middle, from the interosseous ligament, and from the 
back of the radius. Insertion, into the base of the second phalanx 
of the thumb. Use ; these last three extend the thumb. 

Indicator. — Origin, from the back of the ulna, and interosseous 
ligament. Insertion, into the base of the first phalanx of the index 
finger. Use ; it extends the fore-finger. 

MUSCLES OF THE HAND. 

Palmar is brevis. — Origin, from the anterior ligament of the wrist, 
and palmar aponeurosis. Insertion,- into the skin at the inner edge 
of the hand. Use ; it contracts the skin. 

Lumbricales? — These are 



Fig. 68. 



four in number and resemble 
earth-worms. Origin, from the 
the tendons of the flexor pro- 
fundus. Insertion, into the ra- 
dial side of the base of the first 
phalanx of each finger. Use; 
they assist in bending the fin- 
gers. (Fig. 68.) 

Abductor pollicis manus. 2 — 
Origin, from the annular liga- 
ment, trapezium, and scaphoid 
bones. Insertion,mto the base of 
the first phalanx of the thumb. 
Use; it draws the thumb from 
the fingers. 

Opponens pollicis. 5 — Origin, 
from the trapezium and annular 
ligament. Insertion, into the 
radial edge of the metacarpal 
bone, from its base to its head. 
Use; it draws the metacarpal 
bone inwards. 
Flexor brevis pollicis manus.* 5 — It consists of two bellies. The 
external arises from the trapezium and trapezoides, and the annular 
ligament ; and it is inserted into the outer side of the first phalanx of 
the thumb. The internal head arises from the magnum and unci- 
form, and the metacarpal bone of the little finger; and it is inserted 
into the inner side of the base of the first phalanx of the thumb. 
The sesamoid bones are included in these tendons. 

Adductor pollicis manus. 6 — Origin, from the metacarpal bone of 
the middle finger between its base and its head. Insertion, into the 
base of the first phalanx of the thumb. Use ; it draws the thumb 
towards the fingers. 

Abductor minimi digiti manus. 10 — Origin, from the pisiform 




MUSCLES OF THE HAND. 



91 



bone, and annular ligament. Insertion, into the ulnar side of the 
base of the first phalanx of the little finger. Use ; it draws the little 
finger from the rest. 

Flexor parvus minimi digiti. u — Origin, from the unciform pro- 
cess of the unciform bone, and annular ligament. Insertion into the 
ulnar side of the base of the first phalanx of the little finger. Use ; 
it bends the little finger. 

Adductor metacarpi minimi digiti. — Origin, from the unciform 
process and annular ligament. Insertion, into the metacarpal bone of 
the little finger, from its base to its head. Use ; it brings the meta- 
carpal bone towards the wrist. 

Interosseous muscles. — These are seven in number ; three of which 
are on the palmar side, and four on the dorsal side. The palmar 
interossei are adductors, the dorsal are abductors with reference to 
the median line of the hand. 



Fig. 69. 



Fig. 70. 





The palmar interosseous muscles. (Fig. 69.) — These arise from 
the base of the metacarpal bone of one finger, and are inserted into 
the base of the first phalanx of the same finger. The first belongs 
to the index finger, 1 the second to the ring finger, 2 and the third to 
the little finger. 3 

The dorsal interosseous are penniform, arising by two heads from 
adjoining sides of the metacarpal bones. (Fig. 70.) They are in- 
serted into the bases of the first phalanges ; the first into the index 
finger, 1 the second and third into the middle finger, 2 3 compensating 
its exclusion from the palmar group ; the fourth into the ring finger. 4 

The diversified and confused description of these muscles by dif- 
ferent authors, is owing to the use of terms that are not significant, 
a want of proper classification, and the dividing of one muscle in 



92 FEMORAL HEF.M .-. 

two, and calling the different portions of it by different names; thus, 
some enumerate four palmar and three dorsal interossei, together 
with the muscle called abductor indicis ; others, again, enumerate 
four palmar and four dorsal. The principle of classification should 
be with regard to their action. Whether they are abductors, or 
adductors, with reference to an axis passing through the middle fin- 
ger. If the first dorsal interosseous is split into two muscles, and 
that portion arising from the metacarpal bone of the thumb, is called 
the abductor indicis, and the remaining portion counted among the 
palmar interossei, the various modes of classifying these muscles, 
can easily be understood. 

MUSCLES OF THE LOTER EXTREMITY. 
The lower extremity is covered by a dense fascia called fascia 
lata, which commences at the crest of the ilium, and extending over 
the glutei muscles, reaches to the foot. In the front of the thigh 
it is termed iliac and pubic, with reference to its proximity to 
these bones. At the knee, it forms a general covering, called the 
inrolucrum ; in the leg it is termed the crural fascia; in front of 
the ankle it constitutes the annular ligament, which binds down 
the extensor tendons ; under the sinuosity of the os calcis, it binds 
down the flexor tendons in the form of the ligamentum* laciniatum, 
or plaited ligament ; finally, it terminates in the plantar fascia, 
that firm aponeurosis upon the sole of the foot. From it are formed 
numerous sheaths for muscles and tendons. 

AXATOMY OF FEMORAL KERXIA. 

This variety of hernia is a protrusion of intestine at an opening 
near the passage of the large vessels to and from the thigh. We 
shall at first describe the parts as they occur upon dissection, and 
then the descent of the gut. 

Ut: on the removal of the skin from the upper portion of the thigh 
the superficial fascia is brought into view. This fascia is a conti- 
nuation of the superficial fascia of the abdomen, and like it is capa- 
ble of being dissected in laminae. In the groin it contains numerous 
lymphatic glands. It is traversed by the saphena vein, which enters 
the femoral vein, through the saphenous opening of the fascia lata, 
about an inch below Poupart's ligament. 

Having removed this fascia we bring into view the fascia lata of 
the thigh. This fascia is of a pearly white colour and very dense 
structure. It consists of two portions, the sartorial and pectineaL 
The sartorial portion 1 is upon the iliac side, and is connected at its 
upper part with Poupar t* s ligament. It passes in front of the sheath 
of the vessels, and has a crescentic edge on its inner side, called the 
form process. This process limits the saphenous opening on 
its outer side ; and in order that this edge should be distinctly seen, 
a layer of superficial fascia with which it is continuous must be 



FEMORAL HERNIA. 



carefully removed ; this portion of superficial fascia which fills up 
the saphenous opening is often called cribriform fascia. (See Fig. 
60.) 

The superior horn of this crescentic falciform process is twisted 
and inserted in the crest of the pubes, external to, but continuous 
with, Grimbernat's ligament, and is called Hey's ligament. 

The pectineal portion of the fascia lata is upon the pubic side ; 
it is thinner than the sartorial and passes behind the sheath of the 



The sheath of the vessels is formed of condensed cellular tissue, 
and may be considered a prolongation of the fascia transversalis and 
fascia iliaca. It is usually compared to the tubular portion of a fun- 
nel ; the abdominal portions of these fasciae constituting the larger 
and upper part of the funnel. Numerous perforations exist in the 
sheath of the vessels for the passage of veins and absorbents, 
which renders it cribriform. One of these perforations can be seen 
where the sheath is laid open, and also the saphena vein entering 
the femoral vein. 12 Since the artery 13 and vein 13 are cylinders, it 
must be evident that there must be some structure filling up the 
intervening spaces, and also the space 15 between the vein and Grim- 
bernat's ligament, 16 or 

else there would be a Fig. 71. 

deficiency of structure. 
Now this space is the 
crural ring, 15 and is 
filled up with loose 
cellular tissue and a 
lymphatic gland. This 
cellular tissue is call- 
ed by some the crural 
septum, by others fas- 
cia propria and cri- 
briform fascia. A 
weakness of this sep- 
tum between the ca- 
vity and tube of the 
funnel predisposes to 
hernia. The crural or femoral ring is bounded in front by Pou- 
part's ligament ; behind, by the bone ; on the inside by Hey's and 
Gimbernat's ligament ; on the outside by the vein. The femoral 
vessels, 11 13 with their sheath, 13 together with the iliacus internus 7 
and psoas magnus 9 muscle, pass out under Poupart's ligament, and 
thus fill the crural arch. 

The intestine in femoral hernia pursues the following course. 
The peritoneum, as in all other instances, is at first distended and 
forms the hernial sac ; this distension takes place at the crural ring, 




94 



MUSCLES OF THE HIP AND THIGH. 



this being the only spot where it can occur under the crural arch ; 
the crural septum or fascia propria is now stretched and thickened ; 
gradually yielding, it forms the next covering of the gut. With 
these it descends the sheath of the vessels, and when it gets below 
the falciform process, emerges at one of the foramina for veins or 
absorbents ; then it comes in contact with the superficial fascia, 
which forms another covering, and the skin forms the last. 

In reaching the intestine by an operation for hernia, the order of 
coverings would be first, the shin, second, the superficial fascia, 
including that portion of it which some call cribriform fascia, third, 
the fascia propria, which was originally the crural septum, which 
some call cribriform fascia, and fourth, the hernial sac, containing 
the protruding intestine. 3Iuch alteration of structure would of course 
exist by the parts becoming thicker and more laminated. In some in- 
stances the foramen of the sheath is not sufficiently large, and then 
the sheath is distended and consolidated with the other coverings. 
Many restrict the term fascia propria to this consolidated covering. 

A femoral hernia may be concealed either above or below the 
saphenous opening ; then of course the fascia lata will also form one 
of its coverings. (See Sttbgeky.) 

MUSCLES OF THE HLP AND THIGH. 



Fig. 72. 



Gluteus maximus. 9 (Fig. 62) — Origin. From the crest and from 

a portion of the dorsum of the 
ilium, from the sides of the sacrum 
and coccyx, and from the greater 
sacro-sciatic ligament. Insertion. 
Into the upper third of the linea 
aspera, and into the fascia femoris. 
Use. It draws the thigh backwards 
and keeps the trunk erect. 

Gluteus mediits. 8 (Fig. 62.) — 
Origin. From the dorsum of the 
ilium between the crest and semi- 
circular ridge, from between the 
anterior spinous processes, and 
from the fascia femoris. Insertion. 
Into the upper and outer surface 
of the trochanter major. Use; it 
draws the thigh backwards and 
outwards. 

Gluteus minimus. 3 (Fig. 72.) — 
Origin. From the dorsum of the 
ilium, between the semicircular 
ridge and the capsular ligament. 




MUSCLES OF THE THIGH. 



95 



Fig. 73. 



Insertion. Into the trochanter major in front and below that of the 
inedius. Use. It abducts and rotates the thigh inwards. 

Pyriforyiis. 9 — Origin. From the second, third, and fourth bones 
of the sacrum. Insertion. Into top of the trochanter major. Use. It 
rotates the limb outwards. 

Gemini. 10 1S — These are two in number; the superior arises from 
the spinous process of the ischium, and the inferior from the tube- 
rosity of the ischium ; both are inserted in common with the ten- 
don of the obturator internus. 

Obturator internus. 11 — Origin. From the margin of the thyroid 
foramen, the internal surface of the thyroid 
ligament, and from the fascia iliaca. Insertion. 
Into the digital fossa of the femur. 

Quadratics femoris. 13 — Origin. From the 
tuberosity of the ischium. Insertion. Into the 
femur between the two trochanters. 

Obturator extemus. — Origin. From the an- 
terior margin of the thyroid foramen, and liga- 
ment. Insertion. Into the digital fossa at the 
root of the trochanter major. Use. The last 
four rotate the thigh outwards. 

Biceps flexor cruris. 16 — Origin. By a long 
head in common with the semi-tendinosus 
from the tuberosity of the ischium, and by a 
short fleshy one from the lower part of the 
linea aspera. Insertion. Into the head of the 
fibula. 

Semi-tendinosus. 18 — Origin. From the tube- 
rosity of the ischium. Insertion. Into the side 
of the head of the tibia just below its tubercle. 

Semi-membranosus. — Origin. From the ex- 
ternal part of the tuberosity of the ischium. 
Insertion. Into a groove at the posterior and 
internal side of the head of the tibia, and it 
is also connected with the ligament of Wins- 
low and the external condyle of the femur. 

Tensor vaginas femoris.* — (Fig* 73.) Ori- 
gin. From the anterior superior spinous pro- 
cess of the ilium. Insertion. Into the fascia 
or sheath of the thigh. 

Sartorius. 5 — Origin. From the anterior su- 
perior spinous process of the ilium. Insertion. Into the inner side 
of the head of the tibia. Use. It bends the leg and draws it in- 
wards. It is the longest muscle of the body. 

Rectus femoris. 6 — Origin. By two tendons, one from the anterior 
inferior spinous process of the ilium, and the other from the edge 




96 MUSCLES OP THE LEG. 

of the acetabulum. I Into the upper surface of the 

patella. 

Vastus externus. 7 — Origin. From the linea aspera, and trochanter 
major. Insertion. Into the upper and external part of the patella. 

Vastus interims. 8 — Origin. From the linea aspera in its whole 
length, covering the inside of the thigh. Insertion. Into the com- 
mon tendon of the patella. 

Crurseus. — Origin. From the anterior part of the femur as well 
as from the linea aspera. Insertion. Into the patella. 

These four last muscles, often called the quadriceps ft mor is, form 
a common tendon in which is placed the patella, before it is in- 
serted into the tubercle of the tibia. It extends the leg. 

Gracilis. 15 — Origin. From the body and ramus of the pubes. 
Insertion. Into the inside of the head of the tibia. 

Pectineus. 13 — Origin. From the crest of the pubes, and the trian- 
gular face in front of it. Insertion. Into the linea aspera below the 
trochanter minor. 

Adductor long us. 1B — Origin. From the body of the pubes. Z : - 
tion. Into the middle third of the linea aspera. 

Adductor brevis. — Origin. From the body and ramus of the pubes. 
Insertion. Into the upper third of the linea aspera. 

Adductor magnus.^ — Origin. From the body and ramus of the 
pubes, and from the ramus of the ischium. Insertion. Into the 
whole length of the linea aspera. At the junction of the middle and 
lower thirds of its insertion it is perforated by the femoral artery. 
Use. These four last draw the thigh forwards and inwards. 



MUSCLES OF THE LEG-. 

Tibialis anticus 3 (Fig. 74.) — Origin, from the outer side and 
head of the tibia and from the interosseous ligament. Insertion, 
into the base of the internal cuneiform bone, and base of the first 
metatarsal bone. 

Extensor Longus Digitorum Pedis. — Origin, from the head of 
the fibula, the head of the tibia, and from a portion of the inter- 
osseous ligament, and edge of the fibula. Insertion, by four 
tendons into the phalanges of the four lesser toes. 

Peroneus Tertius. 6 — Origin, from the anterior angle of the fibula, 
below its middle. Insertion, into the upper surface of the base of 
the metatarsal bone of the little toe. It looks like a portion of the 
last-named muscle. 

Extensor Proprius PoTlicis Pedis. 3 — Origin, from the lower two- 
thirds of the fibula and interosseous ligament. Insertion, into the 
bases of the first and second phalanges of the great toe. Use; it 
extends the great toe. 

Peroneous Long^isJ — Origin, from the head and upper third of 



MUSCLES OF THE LEG. 



97 



the outer side of the fibula. Insertion, into the base of the meta- 
tarsal bone of the great toe. Use ; it extends the foot and inclines 
the sole outwards. 



Fig. 74. 



Fig. 75. 




Peroneus Brevis. 8 — Origin, from the lower two-thirds of the 
outer surface of the fibula. Insertion, into the base of the meta- 
tarsal bone of the little toe. Use ; it extends the foot. 

Gastrocnemius. — Origin, by two heads from the condyles of the 
femur. Insertion, by the tendo Achillis into the tuberosity of the 
os calcis. 

Soleus. — Origin, from the upper two thirds of the posterior part 
of the fibula, and the middle third of the tibia. Insertion, into the 
tendo Achillis. 

These last two muscles form the calf of the leg, and are called the 
triceps surse. 

Plantaris. — This muscle has the longest tendon in the body. 

9 



98 



MUSCLES OF THE FOOT. 



Origin, just above the external condyle of the femur. Inst 
into the os calcis before the tendo Acnillis. 

Popliteus* (Fig- 75). — Origin, from behind the external condyle 
of the femur. Insertion, into an oblique ridge of the tibia, below its 
head. Use ; it bends the leg and rolls it inwards. 

Flexor Longus Digitorum Pedis Perforans. 7 — Origin, from the 
back of the tibia below its oblique ridge. Insertion, into the bases of 
the third phalanges of the four lesser toes, by four tendons, which 
perforate the split tendons of the flexor brevis. Use; it flexes 
the toes and extends the leg. 

Flexor Longus PoUicis Pedis. 9 — Origin, from the lower two- 
thirds of the posterior face of the fibula. Insertion, into the second 
phalanx of the great toe. Its tendon is connected with the flexor 
longus digitorum pedis. Use ; it flexes the great toe. 

Tibialis Posticus. 6 — Origin, by two heads from the tibia and 
fibula, and from the interosseous ligament. Lisertion, into the tube- 
rosity of the caphoid bone. Use ; it extends the foot. 

MUSCLES OF THE FOOT. 
Extensor Brevis Digitorum Pedis 11 (Fig. 7-4). — Origin, from the 
greater apophysis of the os calcis. Lisertion, by four tendons 
into the backs of the four greater toes. Use ; it extends the toes. 
Flexor Brevis Digitorum Pedis 5 (Fig. 76). — Origin, from the 
larger tuberosity of the os calcis and plantar 
fascia. Lisertion, by four small tendons, 
which are perforated by those of the flexor 
longus, into the second phalanges of the four 
smaller toes. 

Flexor Accessorius. — Origin, from the 
inside of the sinuosity of the os calcis in 
front of its tuberosities. Insertion, into the 
outside of the tendon of the flexor longus, 
at its division. Use ; it assists in flexion. 

Lumbricales Pedis. 7 — Origin, from the 
tendons of the flexor longus. Insertion, into 
the inside of the first phalanx of each toe. 
Use ; they assist in flexion. 

Abductor PoUicis Pedis. 3 — Origin, from 
the internal tuberosity of the os calcis, the 
plantar fascia, and internal cuneiform bone. 
Insertion, into the inner side of the base 
of the first phalanx of the great toe, in- 
I eluding the internal sesamoid bone. Ue ; 

it draws this toe from the others. 

Flexor Brevis PoUicis Pedis. — It consists 
of two bellies, which arise from the calca- 
neocuboid ligament and external cuneiform 



Fig. 76. 





MUSCLES OF THE FOOT. 



99 



bone. Insertion, by two tendons into the base of the first phalanx 
of the great toe, including the sesamoid bones. Use ; it flexes this 
toe. % 

Adductor Pollicis Pedis. — Origin, from the calcaneo-cuboid liga- 
ment, from the bases of the third and fourth and fifth metatarsal 
bones. Insertion, into the tendon of the flexor brevis and external 
sesamoid bone. Use ; to draw this toe towards the rest. 

Abductor Minimi Digiti Pedis.* — Origin, from the outer and 
lesser tuberosity of the os calcis and the metatarsal bone of the 
little toe. Insertion, into the base of the first phalanx of the little 
toe. Use ; it draws this toe from the others. 

Flexor Brevis Minimi Digiti Pedis. — Origin, from the calcaneo- 
cuboid ligament, and from the fifth metatarsal bone. Insertion, 
into the base of the first phalanx of the little toe. Use; it bends 
the little toe. 

Transversalis Pedis. — Origin, from the capsular ligaments of 
the first joint of the fourth and fifth toes. Insertion, into the exter- 
nal -sesamoid bone. Use; it approximates the heads of the metatar- 
sal bones. 



Fig. 77. 



Fig. 78. 





Interosseous Muscles. — These are seven in number, four of which 
are upon the dorsal, and three upon the plantar surface of the foot. 
The dorsal interossei, arise by double heads, and are inserted into 



100 MOUTH. 

the bases of the phalanges. The first is inserted on the inner side 
of the second toe, and is therefore an adductor ; the other three are 
inserted into the outer side of the second, third and fourth toes, and 
are abductors. The plantar interossei arise from the bases of the 
three outer metatarsal bones, and are inserted into the inner side 
of the bases of the first phalanges of the same toes. In their action 
they are adductors. 



SECTION IV. 
VISCERA. 

ORGANS OF DIGESTION. 
MOUTH. 

The Mouth is separated from the nose by the hard and soft palate, 
and communicates behind with the fauces. It is bounded in front 
by the lips, while its floor is formed by the mylo-hyoid muscles, and 
its sides by the cheeks. The space between the lips and the teeth 
is called the vestibule. The mouth is lined by a mucous mem- 
brane, which has a variable degree of thickness, and is thrown into 
folds, which are called frena ; there is one beneath the tongue, one 
in front of the epiglottis cartilage at the root of the tongue, and one 
at the middle of the inner surface of each of the lips. This mem- 
brane is covered with numerous glands, some of which are mucous 
and some salivary. 

Internally the lips are composed of fibres, — which extend from the 
middle of the internal surface of each lip to the gum, — and fat, ex- 
ternally of skin. The upper lip is longer and thicker than the 
lower, and has a vertical depression on the middle of its front sur- 
face called pliiltrum. 

The Gums are formed of the lining membrane of the mouth, much 
thickened ; they have great hardness and vascularity, and but little 
sensibility in health. They include the neck of the tooth, and 
adhere firmly to the periosteum. 

The gums and lips are covered by numerous papillae, which con- 
sist of capillaries and nerves. 

The cheeks are composed of muscle, fat, cellular tissue, glands, 
and blood-vessels, included between skin and mucous membrane. 

TONGUE. 
The Tongue is an oblong, flattened, muscular body, which varies 



TONGUE. 



101 



in size and shape; it is the 

organ of taste, and also of Fig. 79. 

importance in speech and 

mastication. Its posterior 

extremity or root is attached 

to the hyoid bone by yellow 

fibrous tissue. Its anterior 

extremity is called its point 

or tip ; its intervening portion 

its body. 

The mucous covering of the 
tongue is very thick upon its 
upper surface, and very thin 
upon its under surface. Some- 
times the term periglottis is 
applied to the epithelium of 
the upper surface. Upon its 
upper surface are a number 
of projections or papillae of 
various sizes and shapes. The 
largest are eight or nine in 
number, called papillae maxi- 
mee, and are situated at the 
posterior portion of the tongue, 
in two convergent lines ; they 
are surrounded by fossae, the 
largest of which is in the 
middle, and called the fora- 
men cdecum. These larger 
papillae will be found to be 

covered by smaller ones, which are called secondary papillae. The 
smallest papillae are fine and pointed, and are found near the middle 
of the tongue, and are termed filiform. The intermediate papillae 
are most abundant, some of them are conical, others fungiform. 
Each papilla is formed of capillary vessels and a nerve. Different 
functions are attributed to these different' papillae. 

Between the papillee maximae and the epiglottis are a number of 
large mucous follicles. 

Muscles of the Tongue. — Hyo-glossus.* — Origin, from the cornu 
of the hyoid bone. Insertion, into the side of the tongue, some of the 
fibres reaching its tip. 

Genio-hyo-glossus. 5 — Origin, by a tubercle behind the symphysis 
of the lower jaw. Insertion, into the hyoid bone, and into the 
whole length of the tongue. 

Lingualis. 9 — Origin, from the yellow tissue at the root of the 

9* 




102 



PALATE. 



tongue. Insertion, 
muscles. 

Fie. SO. 



into the tip between the two last-mentioned 

Superf.cied.is linguae. — An in- 
distinct layer of muscular fibres 
on the dorsum of the tongue 
under the mucous membrane. 
It seems to curl the lip upwards. 
Transversales lingua. 10 — Are 
scattered fibres which pass from 
the middle line to the edge of the 
tongue ) they extend from the 
tip to the root, and their contrac- 
tions lengthen the tongue. 

Verticales linguae. — These are 
fibres which extend from the 
upper to the lower surface of the 
tongue. 

The tongue is supplied by the 
lingual artery. 

The nerves are the "hypoglossal 
or 9th, which is distributed to its 
muscles ; the lingual or gustatory 
branch of the 5th. which supplies 
the papillae and mucous membrane at the forepart and sides of 
the tongue j and the lingual branch of the glosso-pharyngeal division 
of the 8th ; which sends filaments to the papillas niaximse, and to the 
mucous membrane near the base of the tongue. 




THE PALATE. 

The palate separates the back portion of the nose from the mouth, 
and is divided into two parts. The hard palate consists of the 
palate processes of the superior maxillary and palate bones, covered 
by mucous membrane, which is continuous with that of the mouth, 
but is not so vascular or sensitive as that of other parts. It very 
frequently presents transverse ridges, as well as a ridge in the me- 
dian line. The soft palate is the membranous separation between 
the back portion of the mouth and nose, and consists of a fold of 
mucous membrane stretched transversely, enclosing muscles and 
glands. From its middle there projects the uvula, about three 
quarters of an inch in length ; from each side of the uvula there are 
two divergent crescentic folds of mucous membrane, which are called 
lateral half-arches ; the space between which constitutes the fauces. 

Between the anterior and posterior arches of each side is the 
tonsil gland. The tonsil is about the size of an almond, and consists 
of a collection of large mucous follicles. 



SALIVARY GLANDS OF THE MOUTH. 



103 



Muscles of the palate. — Constrictor isthmi faucium. — A small 
muscle placed in each anterior half-arch, arising from the middle 
of the soft palate, and inserted into the side of the root of the tongue. 
It diminishes the opening into the pharynx. 

Palato-pharyngeus. — Another small muscle, included in the pos- 
terior half-arch, arising from the soft palate, and inserted into the 
side of the pharynx. It draws the palate down and the pharynx up. 

Circumjlexus or Tensor palati. — Origin, from the spinous pro- 
cess of the sphenoid bone, and the contiguous portion of the Eusta- 
chian tube. Insertion, by a tendon, which winds around the hamu- 
lus or hook of the internal pterygoid process, into the posterior and 
crescen tic edge of the palate. Use; to extend the soft palate 
transversely. 

Levator palati. — Origin, from the petrous portion of temporal 
bone and Eustachian tube. Insertion, into the soft palate. Use ; it 
draws the palate upwards. 

Azygos uvulce. — Is in the middle of the uvula and soft palate. 
It arises from the posterior nasal spine. Its contractions shorten 
the uvula. 

SALIVARY GLANDS OF THE MOUTH. 

The salivary glands are of a light pink colour, and their secretion 
is of great service in mastication and digestion. They are three in 
number — the parotid, submaxillary, and sublingual. 

Fig. 81. 




The parotid is the largest of the three : its shape is irregular; it 
has no capsule, and is merely covered by the superficial fascia of the 



104 PHARYNX AND OESOPHAGUS. 

neck. It lies on the side of the face in front of the ear, and beneath 
the skin. It extends in front, so as to cover a portion of the mas- 
seter muscle ; in depth in reaches towards the styloid process, and 
posteriorly it is bounded by the external meatus, the mastoid process, 
and the sterno-cleido-mastoid muscle. Its structure is lobulated, 
and its duct, called the duct of JSteno, 2 traverses the outer face of 
the masseter muscle in a line drawn from the lobe of the ear to the 
end of the nose. It is white and hard, about the size of a crow- 
quill, and perforates the cheek through a pad of fat by a very small 
orifice opposite the second molar tooth of the upper jaw. The ex- 
ternal carotid artery passes through the deeper portion of the gland, 
and it is also traversed by the portio dura nerve. There is sometimes 
found in front of the gland an accessory portion, called socius, or 
accessorius parotidis, whose duct empties into that of Steno. 

The submaxillary gland 3 is much smaller than the parotid, is 
irregularly oblong'in figure and lobulated in structure. It is situated 
in a depression on the internal face of the inferior maxillary bone, 
and covered externally by the skin, superficial fascia, and platysma 
muscle. Its duct 4 is called the duct of Wharton, which empties at 
the side of the frsenum under the tongue by a very small orifice on 
the summit of a papilla ; the coats of this duct are very thin ; the 
gland is traversed by the facial artery as it mounts the lower jaw. 
Sometimes there is an additional gland and duct, called after Bar- 
tolin. 

The sublingual gland 5 is the smallest of the three ; its shape is 
also oblong, and its structure lobulated j it is situated under the 
tongue, between the mucous membrane of the mouth and the mylo- 
hyoid muscle. Its duct or ducts (for they are frequently numerous) 
are called after Rivinus, and empty into or near the duct of 
Wharton. 

THE PHARYNX AND (ESOPHAGUS. 

The pharynx is a muscular and membranous sac, communicating 
with the mouth, nose, oesophagus, larynx, and Eustachian tube. It 
is situated in front of the vertebral column, and extends from the 
basilar process of the occiput to the fourth or fifth cervical vertebra. 
It is funnel-shaped, being larger above than it is below. Its length is 
about five inches, although this varies by contraction and distension ; 
it is never collapsed, for its walls are always kept distended by its 
muscular origins. It consists of three coats, muscular, cellular, and 
mucous. Its external or muscular coat is formed by the following 
muscles. 

The inferior constrictor muscle 9 arises from the cricoid and thyroid 
cartilages. (Fig. 82.) The fibres terminate in those of its fellow 
along the posterior median^line ; those of the upper part are oblique, 
those of the lower horizontal. 



THE PHARYNX AND (ESOPHAGUS. 



105 



Fig. 82. 



The middle constrictor muscle 10 arises from the cornu of the os 
hyoides, and the lateral thyreo-hyoid ligament, and is inserted into 
its fellow in the posterior median line. Its upper fibres ascend ob- 
liquely to £he basilar process of the occiput, and overlap the superior 
constrictor, while its lower fibres are horizontal or descending, and 
are overlapped by the inferior constrictor. 

The superior constrictor muscle is quadrilateral, and arises from 
the pterygoid process of the sphenoid bone, from the upper and lower 
jaw, the buccinator muscles, and the root of the tongue : it is inserted 
into its fellow behind, and also into the basilar process of the occiput. 

The stylo-'pharyngeus muscle 12 has been described before. 

The cellular coat is thin, and merely serves for the transmission of 
vessels and nerves, and the connexion of the external and internal 
coats. 

The internal or mucous coat is a 
continuation of that of the mouth, 
nose, and Eustachian tube, and it is 
covered by a thin epithelium, and 
studded with mucous follicles and 
glands. It is supplied by the pha- 
ryngeal and palatine arteries, and 
by the sympathetic and eighth 
pair of nerves. Its uses are for 
deglutition, respiration, and modu- 
lation of the voice. 

The oesophagus is a canal which 
conveys the food from the pharynx 
to the stomach. It is situated in 
the median line, in front of the 
vertebral column, and passing 
through the posterior mediastinum 
inclines somewhat to the left side 
at its lower part, where it passes 
through the diaphragm. 

Its length is about nine or ten inches, and its diameter is not uni- 
form, gradually increasing as it descends. Its upper portion is the 
narrowest part of the alimentary canal, and hence foreign bodies 
which are too large to pass through the alimentary canal, are gene- 
rally arrested in the neck; its shape is cylindrical, although its 
walls when at rest are in contact. It never contains air. 

It has three coats, the external of which is muscular, and thicker 
than any other portion of the canal. The muscular coat consists of 
two layers ', the fibres of the external are longitudinal, and those of 
the external are circular. The cellular coat attaches the muscular 
and mucous, and serves for the passage of vessels and nerves. The 
internal or mucous coat is continuous with that of the pharynx, and 




106 



ABDOMINAL VISCERA. 



has a number of longitudinal folds when in a state of quiet. It has 
a thick epithelium, and numerous mucous glands and follicles. It 
is supplied by the oesophageal arteries, proceeding from the inferior 
thyroid, aorta, coronary, and phrenic arteries ; its nerves are derived 
from the eighth pair, and from the sympathetic. 

Deglutition is performed by the contraction of its longitudinal 
fibres, which shorten the passage, and by the contraction of its cir- 
cular fibres successively from above downwards. 

VISCERA OF THE ABDOMEN. 



Fig. 83. 



The cavity of the abdomen is divided into nine different regions, 

by the drawing of pa- 
rallel lines vertically 2 3 
through the anterior 
inferior spinous pro- 
cesses, and intersect- 
ing them with two 
other parallel lines 
drawn transversely 1 * 
over the crests of the 
ilia, and over the most 
prominent part of the 
costal cartilages. We 
thus have three re- 
gions above, three in 
the middle, and three 
below. 

They are the epi- 
gastric f in which are 
the left lobe of the 
liver, and a portion of 
the stomach ; the right 
hypochondriac, 5 con- 
taining within it the 
right lobe of the liver, 
the left hypochondriac ', 
containing the spleen, 
a portion of the sto- 
mach, and the liver ; 
the umbilical i in 
which are the small 
intestines, and on either side the lumbar regions; 8 the right lumbar 
region contains the right kidney, and ascending colon j while the left 
contains the left kidney and descending colon; the hypogastric 
region, 9 M in which is a portion of the small intestines and bladder j 




PERITONEUM. 



107 



and the iliac fossae^ the right of which contains the coecuin or 
caput coli, and the left contains the sigmoid flexure. 

PERITONEUM. 

The peritoneum is a thin, transparent membrane, lining the cavity 
of the abdomen, and covering 



most of the viscera that are 
contained therein. It is a 
serous membrane, and there- 
fore a shut sac, following the 
general rule of lining the 
cavity, and covering the or- 
gans contained within. It 
secretes a small quantity of 
fluid in health, which lubri- 
cates the surfaces of the vis- 
cera, so that they readily 
move upon each other and 
the walls of the cavity. It 
also forms ligaments and con- 
nexions whereby the viscera 
are held in their places. 
That portion of the perito- 
neum which passes between 
one viscus and another, or 
from a viscus and the wall of 
the cavity, usually consists of 
two laminae, and is called an 
omentum. There are four 
principal omenta, viz., the 
tro-hepatic, or lesser omen- 



Fig. 84. 




turn, which reaches from the 
lesser curvature of the sto- 
mach to the liver; the gastro- 
splenic, reaching from the left 
extremity of the stomach to 
the spleen; the colic-omentum or meso-colon, which holds the large 
intestine to the posterior wall of the abdomen; and lastly, the 
gastro-colic or great omentum or caul, which passes between the 
stomach and colon ; the last is the largest, and covers the intestines 
like an apron; it appears to consist of four layers, whereas, like the 
rest, it consists but of two. Owing to its great size and the proximity 
of the colon to the stomach, it must necessarily be folded or doubled, 
and thus presents a quadruple appearance. 

Since the peritoneum is a continuous membrane, its whole sur- 
face can be traced in a male subject with the point of a finger, other- 



108 PERITONEUM. 

wise it would not be a single sac. In the female there is a deficiency 
at the extremity of the Fallopian tube. 

Commencing at the umbilicus to trace the peritoneum, it will be 
found to line the anterior wall of the abdomen and under surface of 
the diaphragm, thence to cover the upper and a part of the lower 
surface of the liver, L thence to pass to the stomach, 8 forming thus 4 
the upper lamina of the gastro-hepatic or lesser omentum ; having 
covered the anterior face of the stomach, 13 5 it passes down to form 
one of the laminae of the apparently quadruple omentum — the gastro- 
colic; ascending again it forms another lamina, and surrounding 
the inferior semi-circumference of the colon, it passes to the verte- 
bral column, forming the inferior lamina of the colic omentum, 7 
then we find it including the small intestine forming at the mesen- 
tery; 10 from the vertebral column it can be traced over the upper 
and anterior part of the rectum, R and over the posterior and superior 
portion of the bladder, 13 forming at the vesico-rectal pouch, 11 and 
again we trace it to the umbilicus, the point whence we started. 

But in thus tracing it will be found, by the diagram, that we 
have not traced the peritoneum covering some portions of the viscera 
and abdomen. In the dead subject it is very easy to introduce the 
finger through a narrow passage which is called the foramen of 
Window, although there is no hole or tearing of the peritoneum. 
By looking for the posterior end of the gall-bladder and passing the 
finger under the vessels of the liver, it will be easy to touch the peri- 
toneum covering the posterior surface of the stomach. This cannot 
be demonstrated very clearly from a drawing alone, which repre- 
sents merely a longitudinal section of the abdominal cavity; and 
without explanation it gives the false idea of there being two sacs 
instead of one. In the subject, however, by placing the finger upon 
the under surface of the liver, we trace the peritoneum through the 
foramen of Winslow; there it forms the inferior lamina of the lesser 
omentum, 4 thence it covers the inferior surface of the stomach; 
descending it forms the third and ascending at 6 , it forms the fourth 
lamina of the great omentum ; then it covers the superior convexity 
of the colon, and forming the superior lamina of the colic omentum 
at 7 , it ascends in front of the duodenum and pancreas, PD and passing 
out at the foramen of "Winslow, we can trace upon the posterior and 
inferior portion of the liver, the point of starting. 

The mesentery is formed of two laminae of peritoneum, and serves 
to connect the small intestine to the parietes of the abdomen. Its 
root is about six inches wide, and its inferior edge equals in breadth 
the whole length of the small intestine. Between these two laminae 
of peritoneum are the superior mesenteric artery and vein, lymphatic 
glands and vessels, and branches of the sympathetic nerve, together 
with a portion of fat and cellular tissue. 

The mew-colon is al^o formed of two laminae of peritoneum, and 



THE STOMACH. 



109 



holds the large intestine in its place. The transverse portion is long 
and loose, but on each side in the iliac regions it is short, and binds 
the intestise down very tightly; it also contains between its laminse, 
vessels and nerves, together with some fat and cellular tissue ; that 
portion which is attached to the rectum is called the meso-rectum. 

THE STOMACH. 

The stomach is a conoidal sac, somewhat bent or curved, and is 
situated in the left hypochondriac and epigastric regions. It is 
somewhat flattened anteriorly and posteriorly, and thus presents an 
anterior and posterior face ; its direction is oblique from above 
downwards, and from left to right. The left 3 extremity is much 
the larger, and terminates in a rounded cul-de-sac ; at the superior 
portions of this extremity is the cardiac orifice, where the oeso- 
phagus is continued into the stomach immediately below the dia- 
phragm. The right extremity gradually diminishes in size, and its 
orifice is called pyloric, 9 which is continuous with the small intes- 
tine. The structure of the pylorus is much thicker than that of any 
other portion. 

The stomach is held in its position by the oesophagus and the 
duodenum, as well as by peritoneal reflexions. The right end is 
lower and more anterior than the left. 

The upper and lower 
curvatures of the sto- Fig- 85. 

mach are called the 
greater and lesser cur- 
vatures. 5 6 Near the 
pyloric extremity of 
the stomach, is a slight 
dilatation 7 called an- 
trum pylori. The di- 
mensions of the sto- 
mach are variable, de- 
pending upon the mode 
of life. It consists of 
four coats ; peritoneal, 
muscular, cellular, and 
mucous. 

The walls of the sto- 
mach consist of four 
distinct coats. 

The Serous or Peritoneal coat completely covers the stomach, 
except at the curvatures, where are attached the omenta; the loose- 
ness of the omental connections at these points admits of the dis- 
tension of the remaining coats. 

The Muscular coat is not so thick as that of the oesophagus, and 

10 




11C 



j:££ n 



*ACH. 



its fibres pass both in a eircnlar, 7 longitudinal, 6 and oblit 

tion (see Fig. 86). The muscular fibres which pass 

round the left extremity, constitute the muscle of Gavard. The 

circular fibres are most numerous near the pyloric orifice, and the 

longitudinal fibres are most distinct upon the lesser curvature. 

The latter are the most external, and are a continuation of those of 

:he cesi^L^^us. 

The Cellular or nervous coat connects the muscular and mucous; 
it serves for the transmission of vessels and nerves, and can readily 
be inflated ; when dried, it resembles cotton. 

The Mucous or Villous coat, is a continuation of that of the oeso- 
phagus -j it is soft and thick, of a light pink colour, and is thrown 

Mg. 86. 




into a number of longitudinal rugae or folds, which are particularly 
numerous at the greater curvature, and nearer the pyloric orifice. s 
:See Fig. So.' 

At the pyloric orifiee, the mucous membrane is thrown into a cir- 
cular or semicircular fold, which is called the pylori: 

The epithelium of the mucous membrane of the stomach is thinner 
than that of the oesophagus, and is of the eonoidal variety. 

The surface of the mucous membrane of the stomach presents 
different appearances in different portions. These will be best seen 
by minutely injecting the stomach of a child and washing off the 
epithelium. 

The left extremity and the great body of the stomach will exhibit 
polygonal cells or alveoli, which give it a honeycomb appearance. 

The walls of these cells or pockets, as well as the ridges bet~ 
them, are composed of capillaries united by basement membrane. 



INTESTINES. Ill 

These cells are larger in the cardiac extremity, and very regular 
in their appearance. The bottom of each cell is subdivided into 
smaller ce|ls by the arrangement of the capillaries, and these 
smaller cells are the orifices of the gastric glands or tubuli which 
secrete the gastric juice. Near the antrum pylori the cells or 
alveoli are less numerous and smaller ; and the ridges separating 
them are larger. Towards the pyloric valve there exist conical 
projections, which may be termed gastric villi; these villi are 
smaller than those of the intestine. 

The lesser curvature is supplied by the gastric artery, the greater 
by the right and left gastro-epiploics, and the greater extremity by 
the vasa brevia. The nerves are derived from the par vagum and 
solar plexus of the sympathetic. 



INTESTINES. 
The intestinal canal is from thirty to thirty-five feet in length, and 



is divided into large and small intestine. 

SMALL INTESTINE. 

The small intestine is four-fifths of the length of the whole canal, 
reaching from the pylorus to the large intestine ; it is cylindrical, 
and about one inch in diameter, although there is a gradual dimi- 
nution in diameter as it descends. It consists of four coats. 

The Peritoneal coat 1 is the external coat, and is continuous with 
that portion of the peritoneum forming the mesentery. 

The Muscular coat is thin, and consists of pale fibres ; the super- 
ficial are longitudinal; 3 the re- 
mainder are circular, 3 4 and more 
distinct. 

The Cellular coat connects the 
muscular and mucous, and con- 
tains the vessels and nerves ; 
when inflated with air and dried, 
it appears like cotton, as is the 
case in the stomach. 

The Mucous coat is continuous with that of the stomach, and 
covered with a conoidal epithelium. It is longer than any other, 
and hence must be thrown into numerous folds, which are called 
Valvulse Conniventes ; these are circular and overlapping, and more 
numerous 2 and larger 1 in the upper portion of the intestine than in 
the lower. They differ from other folds of mucous membrane in 
being permanent; distention does not remove them. 

The surface of the mucous membrane is covered with a number 




112 



INTESTINES. 



of papillary projections, called Villi, which render it soft and vel- 
vety. 

Their shape varies in different parts of the intestine ) in the upper 
part of the intestine they are more numerous, and resemble trian- 
gular convolutions; in the lower they are more conical and cylin- 
drical. Their length varies from Jth to |d of a line. Each consists 



Fig. 88. 





of a capillary network united by simple membrane, and communi- 
cating with a small artery and vein. They contain also lymphatics 
(Fig. 88), or lacteals, and a number of granular corpuscles and fat 
cells. The exterior is covered with a conoidal epithelium. 

The glands of the small intestine are the crypts or follicles of 
Lieberkiihn, the glands of Peyer, the Solitary Glands, and Brun- 
ner's Glands. 

The crypts are the smallest of the glandular structures, and con- 
sist of nothing more than pockets or tubes opening by small orifices 
in every part of the intestine. Their diameter is T V tn °^ a ^ ne * 
They are lined by epithelium. 

The Glands or Patches of Peyer. — These are all called agminate. 
They are oval clusters of small, round, flattened vesicles or capsules, 
often filled with a white semifluid matter, and situated beneath the 
mucous membrane. When empty of fluid they are difficult of de- 
tection. Their size varies from half an inch to four inches in 
length. Occasionally they are nine inches long. 

They are more numerous in the lower part of the ileum, opposite 
the mesenteric attachment. There may be twenty or thirty in each 
individual. 



INTESTINES. 



113 




The solitary glands differ Fig. 90. 

from the Agminate or Peye- 
rian only in being separate. 
They are soft, white, rounded 
elevations, scattered over the 
whole surface of the mucous 
membrane of the small in- 
testine. They frequently 
contain a white fluid, but 
like the vesicles of the Peye- 
rian patch, have no orifice 
of discharge. 

JBrunner's glands are small 
round bodies in the upper 
part of the duodenum . Th ey 
are compound glands, con- 
taining lobules and branched 
ducts, which open upon the intestine. 

The mucous membrane of the small intestine is extremely vascular, 
and its absorbents are very numerous. 

The arteries are derived from the superior mesenteric, and the 
nerves from the solar plexus. 

The small intestine is divided into Duodenum, Jejunum, and 
Ileum. 

The Duodenum commences at the pylorus, and is about twelve 
inches in length. It is curved in its direction, and partially defi- 
cient in its peritoneal coat, on account of its being received between 
the two laminse of the colic omentum. Its mucous coat is charac- 
terized by its colour, being tinged with bile, and by the great abun- 
dance of valvulae conniventes in its lower part ; the upper part con- 
tains the glands of Brunner. The ductus communis choledochus 
opens into the duodenum four or five inches from the pylorus, 
through a small elevation or tubercle. 

The Jejunum (from jejunus, empty), constitutes two-fifths of the 
small intestine, and the ileum the remaining three-fifths. Although 
there is no anatomical reason for this division, it being impossible, 
from appearances, to say where the jejunum terminates or the ileum 
begins, yet if a portion of the upper extremity of the jejunum be 
compared with a portion of the lower extremity of the ileum, it 
could be recognised by its diameter, abundance of valvules conni- 
ventes, and the small number of Peyer's Glands. There are fre- 
quently blind pouches, varying in size from one to two inches, along 
the course of this small intestine. 



LARGE INTESTINE. 



The large intestine reaches from the ileum to the anus, and is 

10* 



1U 



INTESTINES. 




Fig. 91. one-fifth in length of the whole 

intestinal canal ; it differs much 
from the small intestine in its 
diameter, and has a sacculated 
appearance. Like the small in- 
testine, it consists of four coats. 

The peritoneal coat is conti- 
nuous with the meso-colon, and 
has numerous folds filled with fat, 
which are called appendices epi- 
ploicse. 

The muscular coat consists of 
two sets of fibres ; the longitudi- 
nal fibres are collected into three 
bands, each about half an inch 
in breadth, which extend to the 
rectum ; the circular fibres are 
also thicker than those of the 
small intestine. 

The cellular coat connects 
the mucous and muscular, and 
contains the blood-vessels and nerves. 

The mucous coat has no valvulas conniventes nor villi ; it is whiter, 
thicker, and coarser, than that of the small intestine. Its follicles 
or crypts are extremely numerous, and more readily discerned than 
in the small intestine. They are very regular and uniform in their 
appearance, and consist of a capillary network, forming a pouch or 
tube lined by conoidal epithelium. There are also some glands 
scattered over the mucous coat of the large intestine, which are 
about half a line in diameter. They consist of a dilated cavity 
with a narrow orifice. 

The epithelium of the large intestine is columnar, and lines the 
crypts and glands. 

The large intestine is divided into the coecum, colon, and rectum. 
The Ccecum is a cul-de-sac 3 (Fig. 91), and the commencement 
of the large intestine, and hence is often called caput coli. It is 
bound down into the right iliac fossa, by the meso-colon; its length 
varies from one and a half to three inches, and its diameter is 
greater than that of any other portion of the alimentary canal, ex- 
cept the stomach. 

The appendix vermiformis, is a worm-like process, of the thick- 
ness of a quill, varying in length from three to six inches, and 
attached to the inferior portion of the coecum. 5 Its coats are the 
same as those of the intestine, and it usually contains flatus. Its 
follicles or crypts are not so numerous or regular in their arrange- 
ment and size as those of the other portions of the large intestiue 
and when injected, show a different arrangement of capillaries. 



INTESTINES. 



115 



The ileo-coscal valve 3 is an elliptical opening on the side of the 
ccecum, between its circular fibres, whereby the small intestine 
empties into the large. It is composed of two crescentic folds, the 
upper of which is the larger. Its action is such that the distention 
of the ccecum will prevent the passage of air or fluids backwards 
into the small intestine. (Fig. 93.) It is also called the valve of 
Bauhin or Morgagni. 

The Colon is the longest portion of the large intestine ; it gra- 



Fig. 9! 



Fig. 93. 




dually diminishes in diameter until it terminates in the sigmoid 
flexure on the left side. 6 (Fig. 92.) It ascends upon the right side, 
and forming an arch transversely, descends upon the left. The 
right side receives its arteries from the superior mesenteric, and 
the left side receives branches from the inferior mesenteric. The 
nerves are derived from the inferior and superior mesenteric plexuses 
of the sympathetic. 

The Rectum is the terminating portion of the large intestine, and 
reaches from the sigmoid flexure to the anus, occupying a position 
in front of the sacrum. It is somewhat barrel-shaped, being larger 
in the middle than at either end. The peritoneal covering is de- 
ficient below and behind. The muscular coat has a very great thick- 
ness and redness. The external fibres are longitudinal, and the in- 
ternal circular. The fibres of the external muscular coat wind 
around the inferior edge of the circular coat, and terminate in the 



116 



THE LIVER. 



mucous coat, which, in some measure, accounts for haemorrhoids 
and prolapsus ani. The mucous coat is thicker and redder than in 
the upper part of the intestine, and at the lower extremity, just 
above the anus, is thrown into a number of pouches between the 
longitudinal muscular fibres. (Fig. 94.) About five or six inches 
above the anus, is a semicircular fold of the mucous membrane on 
each side of the rectum ; these two are about half an inch distant 

Fig. 94. 




from each other ; they resemble the valvulae conniventes, and in 
some measure prevent the involuntary discharges of faeces. — The 
arteries of the -rectum are the superior, middle, and inferior hse- 
morrhoidal. The veins form a plexus around the bowel, which 
communicates with the internal iliac and portal veins. The nerves 
are supplied from the sacral plexus, and from the hypogastric plexus 
of the sympathetic. 

THE LITER. 

The liver is the largest glandular organ in the body, and secretes 
bile. It is oblong and oval in its shape, and occupies the right hy- 



THE LIVER. 



117 



pochondriac, a portion of the epigastric, and left hypochondriac re- 
gions. It weighs from four to five pounds ; it measures from ten to 
twelve inches transversely, and from six to seven antero-posteriorly ; 
its greatest" thickness is from four to five inches. It is convex upon 
its upper surface, and concave upon its lower. Its colour is of a 
reddish brown, with occasional spots of black. It is covered almost 
entirely by peritoneum, which, upon its upper surface, forms a broad 
suspensory ligament, 6 by means of which it is held in contact with 
the diaphragm. In the anterior edge of this ligament, is another, 
of a cordlike character, called lig amentum teres, 6 which was originally 
the umbilical vein. It passes through the anterior notch of the liver 

Fig. 95. 




and umbilical fissure. Posteriorly, the two laminae of the suspen- 
sory ligament diverge, forming the coronary ligament, under which 
the liver is destitute of peritoneum. The lateral ligaments* s are 
also peritoneal, being, in fact, a continuation of the coronary ; they 
are horizontal, and attach the right and left sides of the liver to the 
posterior walls of the abdomen. There is a deep depression upon 
the posterior edge 
of the liver, called 
the posterior notch, 
whereby the liver is 
adjusted to the ver- 
tebral column. The 
anterior and poste- 
rior notch divide the 
liver into two lobes, 
the right of which 
is much the larger 
and thicker, and the 
left terminates in a 
thin cutting edge. 
The under sur- 




118 THE LIVER. 

face of the liver presents a deep fissure, called umbilical or longi- 
tudinal, which reaches from the anterior 16 to the posterior 17 notch, 
and contains the remains of the umbilical vein, now the ligamentum 
teres, and the remains of the ductus venosus. Sometimes this fis- 
sure is converted into a foramen, 7 the right and left lobes being 
connected. At right angles to this fissure is another, called the 
transverse fissure, 1 * which contains the portal vein, hepatic artery, 
and hepatic duct, bound together by cellular tissue, which is called 
the capsule of Glisson. A deep depression upon the under surface 
of the right lobe of the liver, parallel with the longitudinal fissure, 
contains the gall-bladder; 10 that portion of the liver included be- 
tween this depression and the longitudinal and transverse fissures is 
called the lobulus quadratus, 3 or quartus, from its shape. The 
lobidus Spigelii* is a small triangular lobe, at the posterior and in- 
ferior portion of the liver, and with the lobulus quadratus, con- 
stitutes the porta or gateway of the liver. An elongated ridge, 
running from the lobulus Spigelii outwardly, 5 is called the lobulus 
caudatus ; in the angle between the lobulus Spigelii and the right 
lobe of the liver, is a deep fissure, for the passage of the ascending 
vena cava. 3 

There are four sets of vessels for the liver. 

The hepatic artery is a branch of the cceliac, approaches the liver 
at the transverse fissure, and divides into two or three large branches 
previous to entering it. 

The portal vein collects the blood from' all the chylopoietic vis- 
cera, and upon reaching the transverse fissure, divides into two 
large branches, called the right and left sinuses. 

The hepatic duct, commencing by fine branches in the interior of 
the liver, is about the size of a small quill, and is also included with 
the two last vessels by the capsule of G-lisson in the transverse 
fissure. 

The hepatic veins commence also by capillaries in the liver. 
The branches collect and form three large trunks, whose course is 
backwards towards the posterior notch of the liver. These trunks 
appear more like channels lined by a thin venous coat, than the 
ordinary veins. They empty into the ascending vena cava, as it is 
passing through the fissure formed between the lobulus Spigelii and 
the right lobe. 

The structure is best exhibited by tearing the liver ; this shows 
a granulated arrangement, and each of these granules is usually called 
an acinus. Each acinus consists of a terminal branch of the portal 
vein and hepatic artery, together with the incipient radicles of the 
hepatic duct and hepatic vein ; and in the capillary rete thus con- 
stituted are numerous cells, which secrete the bile. (See Physiology.) 

A diversity of opinion exists as to whether these cells are inside 
or outside of the primitive biliary vessels. It is also doubtful 
whether the biliary vessels commence by a rete in each acinus, or 



PANCREAS. 



119 



whether they commence by straight tubes, running between the 
acini, which, coalescing, form the hepatic duct. The aggregation of 
these acini is by means of cellular tissue, called the parenchyma, 
which may be considered as a continuation of Grlisson's capsule. 

GALL-BLADDER. 

It is placed on the under surface of the right lobe of the liver, 
and inclines somewhat to the right side. It is a pyriform sac, of 
about three inches in length ; its anterior extremity is globular, and 
called the fundus ; its posterior end, or neck, is narrow, and twisted 
like a screw. It consists 
of three coats. The ex- 
ternal is formed of the 
peritoneum, 1 and is only 
a partial covering for its 
inferior surface ; the mid- 
dle 3 consists of a strong 
layer of fibrous tissue; 
and the internal is mu- 
cous, 3 with short, irre- 
gular folds, giving it a 
fine net-like appearance; 
its colour is usually that 
of the bile ; in the neck 
it is spirally twisted, and 
thus acts as a valve. Its 
duct, called the cystic 
duct, is shorter and thin- 
ner than the hepatic 
duct, which it joins at a 
very acute angle \ this 
junction forms the ductus communis choledochus, which is about the 
size of a goose-quill, and three inches in length. It passses through 
the right extremity of the pancreas at its posterior portion, and 
perforates the duodenum obliquely and with a very small orifice, 




through an elevated tubercle. Its artery, called cystic, is a branch 
of the hepatic. 

PANCREAS. 

This is a long and flat gland, and of a light pink colour. It is 
placed transversely behind the stomach, and in front of the last dorsal 
and first lumbar vertebrae. It has no peritoneal covering, but is 
included between the two laminse of the meso-colon, and extends 
from the curvature of the duodenum 7 across to the spleen. 1 It is 
about seven inches long. Its right extremity, 6 or head, is much the 
thickest part, is traversed by the ductus choledochus, and often 
called the lesser pancreas. Its left extremity gradually diminishes 
in breadth until it touches the spleen. 



120 SPLEEN. 

The superior edge of the pancreas has a groove for the passage of 
the splenic artery. 8 9 l0 Its structure, like that of salivary glands, 
is conglomerate. Its excretory duct, called after Wirsungius, is * 



Fig. 98. 




formed by a collection of small branches, which come from the lo- 
bules of the gland. The walls of the duct are thin, white, and 
smooth, gradually increasing in size ; it opens into the duodenum 
near the orifice of the ductus communis choledochus, and some- 
times into it. Its arteries are branches of the splenic. 

SPLEEN. 

The spleen is contained in the left hypochondriac region. It is 
a soft vascular organ of a purplish colour. It has no duct, and it is 
therefore not a true gland. 

The shape of the spleen is irregular and variable, but it is gene- 
rally a section of an ovoid, with a convex surface resting against the 
diaphragm, opposite the ninth, tenth, and eleventh ribs, and a con- 
cave surface directed towards the stomach ; this surface is divided 
longitudinally by a fissure or hilum, which transmits the blood- 
vessels. 

It is covered by the peritoneum, which appears wrinkled when 
the spleen is bent. Reflections of the peritoneum from the stomach 
and diaphragm, called gastro-splenic and splenico-phrenic omenta, 
hold the spleen in its position. The edges of the spleen are fre- 
quently notched, and occasionally small additional spleens are found 
connected with it. 

It varies in size more than any other organ in the body. It is 
generally five inches long and three wide, and weighs from five to 
seven ounces. Besides its peritoneal coat, it is covered by an in- 
ternal elastic tunic, which is of a white colour, and composed of 
cellular tissue. In some animals muscular fibres are found in this 
coat. From this tunic are prolonged numerous bands, which traverse 
the organ in all directions. In the interstices of these bands or 
trabeculag the vessels ramify. 



KIDNEYS. 



121 



The proper substance of the spleen is a soft pulpy mass, of a red- 
dish brown colour, resembling grumous blood, contained between the 
trabecules and outside of the venous plexus. It consists of rounded 
granules, about the size of the blood corpuscles. Beside these, there 
are the corpuscles of Malpighi, which are white capsules, varying in 
diameter from the ^yth to ^th of an inch. They contain a soft, 
white, semifluid matter, which is composed of granules, resembling 
in size the red corpuscles of the spleen. The lymphatics of the 
spleen are very numerous. 

The splenic artery is the largest branch of the coeliac, and divides 
into four or five branches before it enters the spleen. The splenic 
vein empties into the portal vein. 



KIDNEYS. 



Fig. 99. 



The kidneys are two hard glands for the secretion of urine, placed 
in each lumbar region, and reaching from the first to the third 
lumbar vertebras ; they are outside of the peritoneal cavity, and sur- 
rounded with an abundance of fat and loose cellular tissue. The 
right kidney is rather lower than the 
left, on account of superposition of the 
liver. The length is four inches, and 
the breadth two inches. The shape is 
oval, resembling a bean ; the position is 
upright, and the fissure or hilum is 
directed inwards towards the vertebral 
column. The upper end of the kidney 
is rather larger than the lower. It is 
covered by a strong fibrous capsule. The 
colour is of a reddish brown. Upon 
making a longitudinal section of the 
kidney, two different structures are pre- 
sented. The internal is of the darker 
colour, and consists of about fifteen cones 
of Malpighi, which are arranged in three 
rows, their apices converging towards the 
hilum. These constitute the medullary 
portion. The external structure is of a 
lighter colour usually, is extremely vascular, and of a granulated 
arrangement ; it constitutes the cortical portion. 

The cortical substance 3 consists of a number of tortuous tubes of 
Ferrein, in which the urine is first formed, and between whose walls 
are a number of small bodies, called the corpuscles of Malpighi. 

Mr. Bowman says that the end of each tube is dilated and re- 
ceives the Malpighian bodies. These bodies are a tuft of capillaries, 
of about T |(jth of an inch in diameter. They are supplied by a small 

11 




122 BLADDER. 

artery, and from them emerges a vein, which afterwards forms a 
rete upon the uriniferous tubes. 

The medullary cone of Malpighi 3 is capable of subdivision into 
small pyramids of Ferrein, and each pyramid of Ferrein will be 
found to consist of a number of straight tubes of Bellini, which are 
the continuations of the tortuous tubes of Ferrein. 

The apex of each cone is called papilla renalis, and in the centre 
of each papilla is a slight depression, called foveola. 

Each papilla is surrounded by a small membranous cup, called 
infundibxdumf into which the urine is first received as it oozes 
from the orifices of the papillae. Four or five of these infundibula 
join to form a common trunk, called calyx, 5 and the junction of about 
three calyces form a common cavity, called the pelvis,* which is of 
a conoidal shape, and from which proceeds the ureter,' 1 the excretory 
tube of the kidney, which conveys the urine to the bladder. 

The ureter* is a cylindrical tube of the size of a quill, with thin, 
white, extensible walls. Crossing in its descent the iliac artery, it 
enters the inferior fundus of the bladder very obliquely, and opens 
by a very small orifice. It consists of two coats, the external of 
which is fibrous, and the internal is mucous. The structure of the 
calyces and infundibula is the same. 

SUPRA-RENAL CAPSULES. 

The capsidce renales 1 (Fig. 99), are two small bodies, varying 
much in size, placed one on each side, just above the kidney, and 
reposing on its upper extremity. They are of a light brown colour, 
and surrounded by condensed cellular tissue. In foetal and youthful 
life they are much larger than in adult life, and hence it is supposed 
that the use is confined to that period of life, as in the case of the 
thymus gland. They are of a triangular or semicircular shape, the 
base being excavated where it is adjusted to the kidney. Having 
no secretion, they of course have no duct. 

They are supplied by the capsular artery, a branch of the renal 
artery or the aorta. 

WOLFFIAN BODIES. 

These structures exist only until the sixth month of foetal life. 
Before this period they conceal the kidney and renal capsule. They 
consist of tubes which empty into the sinus uro-genitalis, a duct 
peculiar to foetal life. 

BLADDER. 

The bladder is a musculo-membranous sac for the reception of 
urine. It is situated in the cavity of the pelvis, behind the sym- 
physis pubis, and in front of the rectum, in the male -, but in the 
female, the uterus and vagina are between the bladder and rectum. 
It is connected with the umbilicus by means of a kind of ligament, 
called the nrachus. 1 (Fig. 101.) 



PENIS. 



123 



Its shape is oval, the larger end being downwards j in women it 
is more spheroidal 5 in children it is pyriform. It is divided into 
a superior -and inferior fundus, a body, and neck. 

Its dimensions vary with health and disease. An ordinary 
healthy bladder will hold nearly a pint. The round ligaments of 
the bladder were formerly the umbilical arteries, and are contained 
in folds of peritoneum on each side of the superior fundus ; besides 
which, the bladder is held in its place by the anterior and lateral 
ligaments, which are processes of the pelvic fascia. 

The bladder has four coats, viz., the peritoneal, which only covers 
the posterior part of the body and superior fundus. The muscular 
coat is thicker than that of the intestine ) the fibres are pale and 
unstriped. The external fibres are more longitudinal, and the in- 
ternal more transverse or circular in their course, and pass in various 
directions. The cellular coat is thick and dense, very distensible 
and impervious to water. It 

connects the muscular and Fig- 100. 

mucous coats and transmits 
the vessels and nerves. The 
mucous coat is soft, smooth, 
and of a light pink colour. 
It is covered by an epi- 
thelium. It has numerous 
follicles, which are exceed- 
ingly small. The vesical 
triangle is a space within 
the cavity of the bladder, 
and included between the 
two orifices of the ureters 2 
and the orifice of the urethra. 
In the anterior angle there 
projects in the bladder the 
uvula vesicae, a prominence 
of the third lobe of the pro- 
state, covered by the mucous 
membrane. Under the mu- 
cous membrane of the vesical 
triangle is a plane of fibres, 3 connected with the orifice of the 
ureters, 3 and that of the ductus ejaculatorius. Surrounding the 
neck of the bladder is the sphincter vesica, which consists of a semi- 
circular 4 and a transverse 5 set of fibres. 1 The latter are partly com- 
posed of yellow elastic fibres. (Fig. 100.) 




The penis conveys the urine from the bladder, and the semen 
into the female. The anterior extremity or head is the glans, 17 the 



124 



PENIS. 



posterior extremity is the root, and the intervening part is the body, 
which consists of two structures, the corpus cavernosum and corpus 
spongiosum. 

Fig. 101. 




The skin of the penis is thin and delicate, and has numerous 
hairs and sebaceous follicles. Surrounding the glans is a loose 
doubling of skin called the prepuce, which is connected to the orifice 
of the urethra by a vertical process called the frcenum. 

The glans has a thick rim or edge around its base, the corona 
glandis, behind which the penis is narrow, and this portion is known 
as the neck or collum. The glands of Tyson are the sebaceous 
follicles, numerous about the neck and crown, and whose secretion is 
called smegma. 

Beneath the skin is the fascia of the penis, which is formed of 
condensed cellular tissue, and is in fact a continuation and modifi- 
cation of the superficial fascia of the abdomen. That portion of the 
fascia which passes from the pubes to the penis is the lig amentum 
suspensorium, which is triangular in shape and vertical in position, 
and antero-posterior in direction. The fascia of the penis may be 
said to be formed by the penis being included between two laminae 
of this ligament. 

The corpus cavernosum forms the largest part of the penis, and 
is in shape a double cylinder. At the root these cylinders are sepa- 
rate and pointed, and called the crura 15 of the penis — each crus is 
firmly attached to the ramus of the pubes and ischium, constituting 
the origin of the penis. Externally the corpus cavernosum is 
covered by a dense, thick, fibrous, and elastic coat. Internally it 
consists of a spongy structure made up of cells, which readily com- 
municate with the arteries and veins. There are some arteries 



PENIS. 125 

which do not terminate, however, in these cells, but in blind tufts, 
called helicine arteries. The two cylinders are partially separated 
from each other "by the septum pectiniforme, a partition which is 
more complete behind than before, and-whose fibres being vertical, 
somewhat resemble the teeth of a comb, whence the name. 

The corpus spongiosum 20 occupies the same position with relation 
to the corpus cavernosum, as a ramrod does to a double-barrelled 
gun ; being contained in a longitudinal groove on its inferior surface, 
the nutritious vessels occupying a corresponding position above. It 
is covered by a dense fibrous covering also, but it is thinner than 
that of the corpus cavernosum. Internally it is composed of cells, 
which are larger than those of the corpus cavernosum. 

Posteriorly it touches the triangular ligament ; this extremity is 
enlarged into what is called the bulb, 21 which lies between the diver- 
gent crura of the penis; anteriorly it forms the glans penis. 17 

The urethra is the urinary canal or tube from the bladder, and 
perforates the corpus spongiosum. It consists of two coats; the 
external is formed of yellow elastic tissue, and a few involuntary 
muscular fibres ; the internal is mucous, and continuous with that 
of the bladder. The course of the urethra is curved and its dia- 
meter varies. 

The first part perforates the upper part of the prostate gland, and 
is termed the prostatic portion ; Q this is an inch in length, and in it 
we find the uvula vesica behind and looking into the bladder ; and a 
triangular elevation of mucous membrane in front, called the caput 
gallinaginis or verumontanum. In front of the caput gallinaginis 
is the utriculus, a small pocket into which empty the ejaculatory 
ducts. On each side there is a groove perforated with the orifices 
of the prostatic ducts. 

The next portion is the membranous ; 10 this is eight or ten lines 
in length, and is very narrow ; it perforates the triangular ligament, 
and it is surrounded by loose tissue, and a few muscular fibres called 
the muscle of Guthrie or compressor urethras. 

The urethra now perforates the bulb of the corpus spongiosum, not 
directly at its pendulous tip, but through its superior convexity just 
in advance of its extremity. This portion is the longest, and com- 
mences with an enlargement called bulbous; 13 gradually it diminishes 
in diameter until it reaches the glans, in which it again enlarges 
and constitutes the fossa navicularis. J3 When the urethra is rer 
laxed, longitudinal folds exist in this portion. Numerous mucous 
follicles are also readily seen, of which the largest is in the fossa. 
The orifices of Cowper's glands open obliquely upon the mucous 
membrane also, about an inch in front of the glands. 

The penis is supplied by the internal pudic arteries and pudendal 
nerves. 

11* 



126 SCROTUM AND TESTICLES. 



VE8ICULJ! SEMISAIES. 

The seminal vesicles consist of two convoluted tubes placed at 
the posterior and inferior portion of the bladder. They are oblong 
in shape, and converge downwards and forwards. Each appears to 
be about two inches in length, but when cleanly dissected and un- 
ravelled, it is a tube five inches in length, with numerous pouches 
or caeca. 

The. duct of the vesicle is joined by the vas deferens on either 
side in the prostate gland j the junction forms the ductus ejacula- 
torius, which, passing through the prostate, opens into the urethra 
in front of the caput gallinaginis. They contain a mixture of 
mucus and semen. 

PROSTATE GLAND. 

This is a dense hard structure, about the size of a horse-chestnut, 
which surrounds the neck of the bladder and the commencement of 
the urethra. It is of a light colour, and somewhat triangular in 
shape, the point being in front. It is placed between the rectum 
which is behind, and the triangular ligament in front. 

It is enveloped in a fascia, which is continuous with the posterior 
lamina of the triangular ligament; it may be divided into two 
lateral and a middle lobe. The urethra perforates the middle lobe, 8 
and the projection of the uvula vesicae and verumontanum are par- 
tially formed by it. 

Its structure is composed of tubes united by condensed and hard 
cellular tissue. The secretion is thick and white, and is discharged 
by orifices into the urethra on each side of the verumontanum. 

Cowper s glands. 11 — These are two in number; placed in front of 
the prostate, and included between the two laminae of the trian- 
gular ligament. They are about the size of a pea, and of a yellow 
colour ; secreting a mucous fluid which is discharged into the ure- 
thra about an inch in front of the gland. 

SCKOTTJM AND TESTICLES. 

The scrotum is a bag-like covering for the testicles, formed exter- 
nally of skin, which is of a dark colour, and thickly covered by 
hairs and studded with sebaceous follicles. The skin is loose and 
thin ; on its middle is a ridge still darker in colour, which reaches 
from the anus to the prepuce, called the raphe. The transverse 
wrinkles of the scrotum which cold produces, are due to a structure 
immediately beneath and intimately connected with the skin, called 
the dartos. 

The dartos is a dense, reddish, contractile covering, divided by a 
partition into two bags. It was once considered muscular, and the 
remains of the gubernaculum testis ; it is principally composed of 



SCROTUM AND TESTICLES. 



vn 



the yellow fibrous elastic tissue, with a few unstriped or involuntary 
muscular fibres. Its contractions are involuntary. 

The position of the testicle in foetal life, and its descent, have 
been noticed under the head of inguinal hernia. Beneath the dartos 
is a covering of intercolumnar or external spermatic fascia, and the 
superficial fascia. 

The cremaster muscle sends a few fibres and loops upon the ante- 
rior and upper part of the testicle, and is sometimes called the tunica 
erythroides. 

The next covering is that derived from the fascia transversalis and 
infundibuliform fascia. It is sometimes called the internal sper- 
matic fascia, and also tunica vaginalis communis testis; by Cooper 
it is called the fascia propria. 

The tunica vaginalis or peritestis, is the next covering. It is a 
serous membrane lining the cavity and reflected over the testicle 
within ; it was originally peritoneum, and is the seat of hydrocele. 

The testicles are the glands for the secretion of semen. They 
are two in number, oval in shape, and flattened laterally. They 
hang obliquely by the spermatic cord, being attached above the 
middle of the posterior edge; the right is higher than the left. 

The tunica albuginea, 2 is the dense, white, thick, fibrous coat of 
the testicle, which gives it shape. In structure it resembles the 

Fig. 103. 





dura mater or sclerotica ; externally it is covered by a portion of 
the peritestis, which is transparent and very closely adherent ; 
from its internal face are given off numerous partitions called sep- 



128 SPERMATIC CORD. 

tulse testes, and which, uniting at the posterior edge of the testicle, 
form that prismatic ridge termed corpus IfigTimorianum. 3 

The testicle is formed by lobules, each placed within the spaces 
between the septula?. Each lobule 3 consists of a very fine tube, 
very finely convoluted. Upon its exterior is a capillary network of 
bloodvessels; interiorly it is lined by epithelium. This tube (tu- 
buJus seminiferus), becoming straight forms the vas rectum;* the 
union of the vasa recta makes the rete testis, 5 which is in the corpus 
Highmorianum ; from the upper part of this rete proceed 15 or 20 
tubes through the tunica albuginea j they are called vasa efferentia ; 6 
each vas efferens is convoluted in a conical form, and termed conus 
vasculosis; the union of the coni vasculosi forms the commencement 
of the epididymis. 

The epididymis 8 is that vermiform appendage encircling the pos- 
terior edge, as a crest upon a helmet. It is soft and formed of a 
single convoluted tube, originating by the junction of the bases of 
the coni vasculosi. The upper extremity is the larger, and called 
globus major, 7 and the lower is globus minor* From the globus 
minor this tube ascends in a less convoluted form, under the name 
of the vas deferens* which forms one of the constituents of the 
cord. Connected with the epididymis is the vasculum aberrans™ 
a small, blind, convoluted duct. 

SPERMATIC COED. 

Each spermatic cord consists of an artery and vein, and nerves, 
together with the duct, vas deferens. These constituents are united 
by cellular tissue, which may be the remains of that canal of peri- 
toneum peculiar to fcetal life. 

It is covered by the fascia transversalis prolonged from the abdo- 
men, by the cremaster muscle, which has been previously described ; 
and by the external spermatic or infundibuliform fascia. 

The spermatic artery comes from the aorta, and sometimes from 
the renal. It is tortuous, and after passing through the rings di- 
vides into two or three branches ; the termination of the artery is 
larger than its origin. 

The spermatic veins are very tortuous and numerous, and on 
account of their vine-like appearance are termed vasa pampini- 
formia. They are the seat of circocele. 

The external spermatic nerves, and also branches of the abdomi- 
no-crural, supply the muscular structure; filaments of the sympa- 
thetic run also to the testicle. 

The vas deferens is a continuation of the epididymis. Passing 
through the cord and rings, it descends behind the bladder and joins 
the duct of the vesiculse seminales. It is very hard, and readily 
recognised by touch ; its walls are extremely thick, and its bore 
almost capillary. It is nearly white, and thicker than a knitting- 
needle. 



TELVIC FASCIA. 



129 




THE PERINEUM. 

The perineum re that space included between the anus, arch of 
the pubes, % andthe tu- 
berosities of the ischia. Fig- 104. 

In a proper dissection 
the removal of the skin 
reveals the superficial 
fascia, which is conti- 
nuous with the superfi- 
cial fascia of other parts 
of the body. When this 
is removed, the peri- 
neal fascia is exhibited, 
which is a dense, thin, 
and tough fascia, 17 ad- 
hering to the rami of 
the pubes and ischium 
on each side ; in front 
it is continued into the scrotum ; behind it is continuous with the 
base of the triangular ligament by its anterior lamina, 16 and also 
with the anal fascia, 19 a portion of the pelvic fascia. It covers the 
muscles of the perineum and sends processes between them. Poste- 
riorly it winds around the transversus muscle to join the triangular 
ligament. Its connections laterally and behind account for the 
course taken by extravasated urine from rupture of the urethra. 

The triangular ligament 15 called also deep perineal fascia, lies 
under the muscles of the perineuria fills up the arch of the pubes, 
and is shaped as its name implies. It is a fibrous membrane, sepa- 
rating the pelvis from the perineum. The base, which is not so dense 
and fibrous as its apex, joins the perineal and anal fascia. 21 It is 
perforated by the membranous portion of the urethra, about one 
inch below the symphysis. 

It consists of two laminae, ,G S1 between which are situated Cowper's 
and the prostate gland; 7 thus the fascia of the prostate, as it is 
usually called, is merely the posterior lamina of the triangular 
ligament. 

PELVIC FASCIA. 

This fascia is continuous with the transversalis and iliac fascia 
surrounding that portion of the peritoneum which lines the pelvis. 
Like all fascise, it is easily divided into laminae j different portions 
receiving different names. 

It may be said to commence at the brim of the pelvis, and by its 
intervention the different viscera are united with each other, and held 
in their proper positions. Thus, two processes of it on the sides of the 



130 



MUSCLES OF THE PERINEUM AND ANUS. 



bladder form the anterior ligaments of the bladder. A layer cover- 
ing the obturator muscle is called the obturator fascia. The levator 
ani muscle is included between two layers of this fascia ; that portion 
between the rectum and bladder is called the recto-vesical fascia ; and 
that which covers the lower part of the rectum is the anal fascia. 

MUSCLES OF THE PERINEUM AND ANUS. 

Erector penis. 3 — Origin, from the tuberosity of the ischium. 
Insertion, by a broad flat tendon into corpus cavernosum. 

Accelerator urince, 1 or ejaculator seminis. — It lies on the bulb of 
the corpus spongiosum. Origin, from the cms of the penis, and 
the ramus of the pubes ) and also by a tendinous membrane which 
is between the corpus spongiosum and corpus cavernosum, and is con- 
tinuous with the fascia of the penis. The fibres are semi-pennate, 
and with those of its fellow surround the bulb. Insertion, by a white 
tendinous line into its fellow, and into the perineal centre, which is 
formed by the junction of several muscles. 

Transversus perinei.* — Arises from the tuberosity of the ischium, 
and is inserted into the perineal centre. Sometimes there is an 
additional portion in front, called transversus perinei alter. 

Sphincter an i. 6 — A thick muscular ring surrounding the anus. Its 
superficial fibres are elliptical. It is connected with the coccyx 
and perineal centre. 

Fig. 105. 




Coccygeus. 10 — Origin, from the spine of the ischium. Insertion, 
into the side of the coccyx and last bone of the sacrum. 

Sacro-coccygeus. — A few fibres passing from the sacrum to the 
coccyx in front. 



LARYNX. 



131 



Levator ani. 7 — Is a plane of muscular fibres. Origin, from the 
interior of the body of the pubes, the superior edge of the thyroid 
foramen, the upper edge of the obturator fascia, and the spine of 
the ischium. Insertion, by converging and descending fibres into 
the lateral* semi-circumference of the rectum ; also in the coccyx 
and perineal centre. 



ORGANS OF RESPIRATION AND CIRCULATION. 

LARYNX. 

The larynx is a canal formed of cartilages, which move in such 
a manner as to regulate the voice. 

It is situated in the upper and anterior part of the neck, in the 
median line, below the hyoid bone. 

It forms the commencement of the windpipe ; is cylindrical below 
but prismatic above; it is larger in males than in females. 

The cartilages of the larynx are five in number ; thyroid, cricoid, 
two arytenoid, and epiglottis. 

The thyroid is the largest; it occupies the upper and anterior 
portion of the larynx. It con- 



sists of two quadrilateral plates, 
which are united in an acute 
angle in the median line in front; 
this angle is usually called the 
pomum Adami, 6 which is much 
larger in men; it has a deep 
notch at its upper part. 4 The 
upper edge 3 is curved, and has 
the middle thyreo-hyoid ligament 
attached to it; the lower edge 6 
is also curved, and to it is at- 
tached the middle crico-thyroid 
ligament. The posterior edge 
terminates in two processes called 
cornua, of which the superior 3 is 
the longer, and is attached to 
the lateral thyreo-hyoid ligament. 



Fig. 106. 




The inferior cornu 9 is short and 



curved, and receives the lateral crico-thyroid ligament. Upon the 
external surface 1 is an oblique ridge, passing between two tubercles, 
from which arise the thyreo-hyoid and inferior constrictor muscles. 
The cricoid cartilage is next in size (Fig. 107), and situated at 
the base of the larynx ; its form is that of a thick ring compressed 
laterally ; its lower edge 3 is circular, and attached to the trachea ; 
its upper edge is oval and oblique, on account of the cartilage being 
three times as thick behind as it is in front ; the posterior portion 
of the superior edge has two heads 4 of a peculiar convexity, for arti- 
culating with the arytenoid cartilages ; the external surface poste- 



132 LARYNX. 

riorly is flattened, giving origin to the posterior crico-arytenoid 
muscle. 

Eie. 107. Fig. 108. Kg. 109. 






The arytenoid cartilages are situated at the upper and back por- 
tion of the larynx. They are two in number, and are of a pyramidal 
shape. The base 3 is concave, and articulates with the heads of the 
cricoids ; the apices 8 have attached to them a small cartilage called 
cornicvlum laryngis. or tubercle of Santorini. The posterior sur- 
face 1 is triangular and concave, for the insertion of the posterior 
crico-arytenoid muscle : the internal surface is flat, and can be 
adjusted to its fellow; the anterior or external surface is uneven, to 
which are attached the superior and inferior thvreo-arvtenoid liga- 
ments. (Fig. 108.) 

The epiglottis cartilage is a thin. oval, cartilaginous plate, behind 
the root of the tongue, and attached to the angle of the larynx ; it 
resembles a leaf in shape ; its direction is vertical ; its inferior ex- 
tremity 4 is narrow and pointed ; its superior edge is thin, its ante- 
rior surface 1 is slightly convex, and its posterior- concave. It is 
perforated by numerous foramina. (Fig. 109.) 

These cartilages are held together by numerous ligaments, of 
which the principal are, the middle thyreo-hyoid ; a thin membra- 
nous expansion between the inferior circumference of the hyoid bone 
and the superior edge of the thyroid cartilage : the lateral thyreo- 
Ivyoid ; which is funicular, extending from the great cornu of the 
thyroid cartilage to the tubercle of the cornu of the hyoid bone ) in 
it is found a small oval cartilage or bone, called cartilago triticea ; 
the middle crico-thyroid. a thick membrane, filling up the space be- 
tween the superior edge of the cricoid and inferior edge of the 
thyroid cartilages : this is usually divided in the operation of laryn- 
gotomy ; and the lateral crico-thyroid, reaching from the inferior 
cornu of the thyroid to the side of the cricoid; a capsular ligament 
surrounds the joint between the arytenoid and cricoid. 

"Within the larynx are two thyreo-arytenoid ligaments on either 



LARYNX. 



133 



side. The inferior ligaments extend from the angle of the thyroid 
to the base of the arytenoid, and are usually called the vocal cords ; 
the space between, them is the rima glottidis. The superior liga- 
ments extend from the angle of the thyroid to the middle of the 
arytenoid cartilages. The space between them is the glottis. These 
ligaments are not cords, as they appear to be, but merely edges of 
a membrane lining the larynx, and composed of yellow elastic 
fibrous tissue. 

The mucous membrane lining the larynx is continuous with that 
of the mouth, and forms numerous folds between the cartilages, of 
which the most remarkable is a pouch between the superior and 
inferior thyro-arytenoid ligaments, which has been called the ven- 
tricle of the larynx, or ventricle of Galen. To the ventricle of 
either side is attached an additional pouch, which is called the sinus 
of Morgagni. In the fold between the arytenoid and epiglottis car- 
tilages is a small gland, called the arytenoid, which is of the shape 
of the letter L. 

The muscles of the larynx move the various cartilages, and modu- 
late the voice. 

Thyreo-hyoid. — This was described with the muscles of the neck. 

Crico-thyroid, arises from the anterior and lateral surfaces of the 
cricoid, and passes backwards to be inserted into the inferior cornu 
of the thyroid j it draws these two cartilages together obliquely. 

Posterior crico-arytenoid,' 1 arises from the flat surface on the back 
of the cricoid, and is inserted into the posterior part of the base of 
the arytenoid ; it draws the arytenoid backwards, and thus tightens 
the vocal ligaments. (Fig. 110.) 

Lateral crico-arytenoid. s — Arises from the side of the cricoid, 
and is inserted into the side of the base of the arytenoid ; it sepa- 
rates the arytenoid from its fellow, and widens the glottis. 

Thyreo-arytenoid. 8 — Arises from the posterior face of the thyroid 
near the angle, and is in- 



serted into the anterior 
surface of the arytenoid, 
which it draws forwards, 
and thus relaxes the vocal 
ligaments. 

Oblique arytenoid. 5 — 
They consist of oblique 
fibres arising from the top 
of one cartilage, and in- 
serted into the base of ano- 
ther. (Fig. 111.) 

Transverse arytenoid. 6 
— Arises from the side of 
one cartilage, and is in- 



Fig. 110. 



Fig. 111. 




12 



134 



TRACHEA. 



serted into the side of the other. These last two muscles are often 
considered as one, and by them the glottis is narrowed. 

Thyreo-epiglottideus. — Consists of a few fibres passing between 
these two cartilages. 

Aryteno-epiglottideus. — A few indistinct fibres passing between 
the cartilages from which it derives its name. These last two draw 
the epiglottis downwards. 



TRACHEA. 



The trachea is a cylindrical tube, four or five inches in length, 
reaching from the larynx as low as the third dorsal vertebra, where 
it divides into the hronchi. It is formed of from sixteen to twenty 
rings of cartilage, united by ligamentous tissue, which is of an 
elastic character. Each ring is about two lines broad and con- 
stitutes two-thirds of a circle ; the first ring is the largest, and the 
last ring is of such a shape as to be adapted to the first rings of the 
bronchi. 



Fig. 112. 




The posterior third of the trachea is completed by an involuntary 
muscular structure, whose fibres are transverse, and the contraction 



THE LUNGS. 135 

of which diminishes its diameter, by which expectoration is facili- 
tated ) it is lined by a mucous membrane continuous with that of 
the larynx, which. is extremely vascular, and covered with numerous 
follicles. At the bifurcation of the trachea into the bronchi, there 
are a number of hard, black glands, which are lymphatic in their 
character, and called bronchial from their position. 

The bronchi are essentially of the same structure and arrangement 
as the trachea ; the right bronchus is shorter, and of a larger diameter 
than the left j they soon ramify into numerous subdivisions, which 
finally terminate in the lobules of the lungs. In the smaller ramifi- 
cations of the bronchi there is some modification of structure ; the 
tube is no longer flattened behind, because the cartilages form com- 
plete circles ; the cartilages are less numerous ; each cartilaginous 
ring is not composed of a single piece, but of several segments of a 
circle j there is also a semilunar cartilage at each of the lesser bifur- 
cations. 

TnYKOID GLAND. 

!t is situated in front of the first two rings of the trachea, and upon 
the sides of the larynx ', it consists of two lateral lobes, placed on 
either side, united by a narrow isthmus in front ; it is extremely 
vascular, of a reddish-brown colour, and of tolerably firm con- 
sistence. A process called the pyramid or middle lobe sometimes 
extends from the isthmus to the hyoid bone. Occasionally a small, 
narrow muscle attaches one lobe to the hyoid bone. It is granular 
in its structure, has no excretory tube, but very large lymphatic 
vessels. It consists of minute closed vesicles, surrounded by capil- 
lary vessels, and invested by areolar tissue. These vesicles are com- 
posed of an external capsule, and a yellow fluid containing corpus- 
cles resembling cell-nuclei : albumen enters largely into the compo- 
sition of the fluid. It is supplied by the superior and inferior 
thyroid arteries. It is sometimes much enlarged, constituting bron- 
chocele or goitre. 



THE LUNGS. 



The lungs are the organs of respiration properly ; they are two 
in number, and situated in the thorax, placed side by side, being 
separated from the abdomen by the diaphragm. The size varies 
with the capacity and condition of the thorax, age, inspiration, ex- 
piration, and disease. They are conical in shape, are longer pos- 
teriorly than anteriorly, and have concave bases. The colour of the 
lungs is of a pinkish-gray, mottled with black ; these black spots 
are more numerous in adult life than in infancy. 

The right lung is shorter but larger than the left, whose trans- 
verse diameter is somewhat diminished by the position of the heart. 
It has three lobes, the left having but two. 

The structure of the lungs is spongy, and its compression between 



136 



PLEURA. 



the fingers produces a crackling called crepitation. It consists of a 
number of air-vesicles held together by cellular tissue, called paren- 
chyma ; through which blood-vessels and air-vessels are ramified. 
A certain number of air-cells communicate with each other, and 

Fig. 113. 




with a single branch of the bronchial tube; these are separated 
from neighbouring cells by partitions of parenchyma, and thus are 
formed lobules. These subdivisions are evident upon the external 
surface of the lung. The air-vesicles are formed of ligamentous 
tissue lined by a mucous membrane. 

The root of the lung, consists of the bronchus, pulmonary artery, 
two pulmonary veins, bronchial artery and vein, nerves, and lym- 
phatics. These enter upon its internal surface, and in some degree 
retain the lung in its proper position. The branches of the pulmo- 
nary artery terminate in capillaries, upon the walls of the air-vessels, 
from which arise the branches of the pulmonary veins. 

The bronchial artery is the nutritious artery of the lung. Its 
nerves are derived from the sympathetic, and eighth pair. 



PLEURA. 



The pleura is a serous membrane investing each lung, and then 
reflected upon the parietes of the chest. That portion in contact 
with the chest is called pleura costalis ; that covering the lung, 
pleura pulmonalis. It also covers the diaphragm and the root of the 
lung, between which there exists a fold called ligamentum pulmonis. 



THE HEART. 137 



MEDIASTINUM. 



The space between the two pleurse of the lungs is called the 
mediastinum, and it is divided, by the position of the heart, into 
the anterior, posterior, and superior mediastinum. 

The anterior mediastinum is that space between the sternum and 
the heart; it contains some loose cellular tissue, and a portion of 
the remains of the thymus gland. 

The posterior mediastinum is that region between the vertebral 
column and the heart, and through it passes the oesophagus, par 
vagum nerve, aorta, vena azygos, and the thoracic duct. 

The superior mediastinum is above the heart, and surrounded by 
the first ribs and sternum ; it contains the roots of the large vessels, 
and the remains of the thymus gland. 



THTMU3 GLAND. 



This is a triangular body of a pinkish hue, occupying a portion 
of the superior and anterior mediastina. It grows until the end 
of the second year, after which it diminishes, and almost entirely 
disappears. It has a large lymphatic vessel, which has been sup- 
posed to be an excretory duct. Its structure is lobulated, and sur- 
rounded by loose cellular tissue. Each lobule contains several 
membranous cells or vesicles, which contain a white fluid and open 
into a central cavity or reservoir. The fluid contains corpuscles re- 
sembling the white blood corpuscle and the chyle corpuscle. 

PERICARDIUM. 

The pericardium is a membranous sac, in which the heart is con- 
tained. It consists of two layers, the external of which is fibrous, 
dense, and white, and the internal is serous. The serous lamina 
lines the fibrous layer, and then is reflected over the heart and the 
roots of its vessels. 



THE HEART. 



The heart is a hollow muscular organ, surrounded by a membra- 
nous sac called the pericardium. It is situated between the two 
pleurae, and rests upon the cordiform tendon of the diaphragm, in 
the cavity of the thorax. 

Its shape is conoidal, though it is somewhat flattened upon that 
side which rests upon the tendon of the diaphragm. Its apex in- 
clines to the left side, touching the walls of the thorax, between the 
fifth and sixth ribs. It measures five inches and a half from its apex 
to its base, three inches and a half in the diameter of its base, and 
weighs about six or eight ounces. It contains four cavities, which 
perform two functions, that of receiving the blood and throwing it 
into the lungs, and that of receiving it again after it has been oxyge- 
nated, and distributing it throughout the body. The receptacles are 

12* 



138 



THE HEART. 



auricles, and the ventricles propel the blood to the lungs and through 
the system. 

The auricle and ventricle of the right side receive and propel the 
venous blood into the lungs. The auricle and ventricle of the left 
side receive and propel the arterial blood throughout the body. 

The circulation of the blood is as follows : the ascending and de- 
scending vena cava empty the venous blood into the right auricle ; 
from here it passes to the right ventricle, through an opening pro- 
tected by a valve opening downwards ; from the right ventricle it 
is propelled through the pulmonary artery, which divides into 
two branches, to the lungs ; after it has been subjected to the in- 
fluence of the respiratory process, it is brought from the lungs, by 
four pulmonary veins, into the left auricle. The left auricle has an 
opening into the left ventricle, protected by a valve opening down- 
wards, and from the left ventricle it passes into the aorta, thence to 
be distributed throughout the body. 

The right auricle 1 is an irregularly-shaped cavity, somewhat ob- 
long and cuboidal ; anteriorly it has a convexity which is called its 
sinus ; superiorly there is an elongated process resembling the ear of 
an animal, whence the term auricle. Its walls are thin, and com- 
posed of muscular fibres, which from their parallel arrangement re- 
semble the teeth of a comb, and hence are called musculi pectinati. 
The superior 5 and inferior vena cavse enter the auricle from behind, 
and between their orifices there is an elevation, called tubercidum 
Loweri. On the septum or partition between the auricles, is a de- 
pression called fossa ovalis, where formerly existed the foramen 
ovale of foetal life ; the ring or edge surrounding it, is called the 
anmdis ovalis, from which there extends downwards to the inferior 
semi-circumference of the ascending cava, a crescentic doubling of 
the lining membrane, which is the remains of the Eustachian valve. 
The coronary veins open into this cavity, 
and their orifice is protected by the valve 
of Thebesius. The opening to the ventri- 
cle, called the ostium venosum, is circular 
and surrounded by a dense white line. 

The right ventricle 3 is a triangular cavity, 
with thick walls, and of greater capacity 
than any other cavity of the heart. Its 
muscular structure is in the form of large 
fleshy bundles, called columnse carnese, 
from which proceed thin, white cords, called 
chordae tendineas, which are attached to the 
edge of the tricuspid valve. The tricuspid 
valve is circular, and its upper edge is at- 
tached to the tendinous line of the ostium 
venosum ; its lower edge has three spear- 



Fig. 114. 

8flSl JL'O 




THE HEART. 139 

pointed or leaf-like processes, whence its name; since it opens down- 
wards, the contraction of the ventricle closes the ostium venosum, and 
prevents the blood from returning into the auricle, and therefore it 
passes out by the pulmonary artery. The orifice of the pulmonary 
artery is protected by three valves opening outwards, which are called 
semilunar valves, formed by three crescentic folds of the lining mem- 
brane ; in their loose edges there is often a small tubercle, called corpus 
Aurantii : the use of these valves is to prevent the blood returning 
from the artery to the ventricle, when it dilates. Behind each valve 
is a pouch or dilatation, called the sinus of Valsalva, into which the 
blood flows by its reflux tendency, upon the dilatation of the ventri- 
cle, and thus these valves are closed. The pulmonary artery is of 
the same diameter as the aorta, but its walls are thinner ; after its 
origin it curves upwards and backwards, and divides into two 
branches, the right of which is larger than the left/ and passes 
under the arch of the aorta. 

The left auricle* is more concealed in its natural position than the 
right. Into it enter four pulmonary veins, which give it a quad- 
rangular shape. Its walls are muscular, and somewhat thicker than 
those of the right auricle. In its ear-like appendage the muscular 
fibres are arranged as musculi pectinati ; the opening, by means of 
which it communicates with the left ventricle, is called ostium veno- 
sum, and surrounded by a white tendinous ring. The septum be- 
tween the auricles is not always perfect even in adult life. 

The left ventricle. 4 — This cavity forms the apex of the heart ; it 
is conoidal in its shape. Its walls are thick, and its columnar carnece 
numerous, strong, and projecting; the cJwrdse tendinese are well de- 
veloped, and attached to the bicuspid or mitral valve. This valve 
consists of but two leaflets, one of which is much larger than the 
other ; its base is attached to the ring surrounding the ostium veno- 
sum, and its edge opens downwards into the left ventricle : hence the 
contraction of the ventricle closes this opening, and the blood passes 
out by the aorta, 6 at whose orifice there are three semilunar or sig- 
moid valves, each having a corpuscle of Arantius in its edge, and 
sinuses of Valsalva or Morgagni behind them. The vessels supply- 
ing the heart with blood are the right and left coronary arteries; 11 12 
the veins which accompany them empty by a common trunk into the 
right auricle. The nerves are derived from the cardiac plexuses of 
the sympathetic. 



140 



AORTA. 



section y 

VESSELS. 



STRUCTURE OF ARTERIES. 

Arteries are composed of three coats ; external, middle, and in- 
ternal. 

The external is firm and strong, formed of condensed cellular 

tissue ; it does not yield 
Fig. 115. upon the application of a 

ligature. 

The middle is formed 
of elastic, fibrous tissue, 
and was formerly called 
the muscular coat. It is 
thick, and its fibres are 
arranged circularly j in 
which direction they rea- 
dily yield, to a ligature. 
It contains a few involun- 
tary muscular fibres. 

The interned is a thin, 
serous covering, which di- 
minishes the friction of 
the passage of the blood. 
It is smooth and transpa- 
rent, and readily torn. 

Arteries convey blood 
from the heart, and veins 
carry blood to the heart ; 
thus, the pulmonary ar- 
tery conveys blue or what 
is usually called venous 
blood, and the pulmonary 
veins convey red or what 
is termed arterial blood. 

The nutritious vessels of the arteries are called vam vasorum, and 
their nerves are derived from the sympathetic. 

AORTA. 

The aorta arises from the left ventricle opposite the articulation 
of the fourth costal cartilage with the sternum. At first it ascends 
to the right, then curves backwards and to the left, and descends on 
the left side of the vertebral column to the fourth lumbar vertebra. 




EXTERNAL CAROTID. 



141 



The ascending aorta is partially covered in front and at its origin 
by the pulmonary artery. The upper edge of the arch is on a level 
with the second dorsal vertebra, and under it passes the right pul- 
monary artery. It is frequently enlarged into a sinus in old per- 
sons. Thte descending aorta 3 while passing through the thorax is 
termed thoracic, and while passing through the abdomen, abdo- 
minal. 

The coronary arteries are the first branches of the aorta, and are 
distributed to the heart, through the grooves between the auricles 
and ventricles. They arise just beyond the semilunar valves. 

The Innominata. 4 — This artery arises from the arch of the aorta, 
is an inch and a half in length, ascends obliquely towards the right 
side in front of the trachea, and behind the transverse vein. Oppo- 
site the sterno-clavicular articulation, it divides into the right carotid 
and right subclavian. (Fig. 115.) 

The right carotid 5 arises from the innominata, and ascends the 
neck as far nearly as the hyoid bone, where it divides into the ex- 
ternal and internal carotids. 



The left carotid 11 ari- 
ses from the arch of 



Fig. 116. 



liquely through the tho- 
rax until it reaches the 
neck, and then it is dis- 
tributed as the right. 
Each primitive carotid is 
on the inner side of the 
internal jugular vein, 
with which and the par 
vagum nerve it is in- 
cluded in a sheath. (Fig. 
115.) 

EXTERNAL CAEOTID. 

(Fig. 116.) 
It ascends perpendi- 
cularly from the bifurca- 
tion of the carotid, and 
passing through the deep 
portion of the parotid 
gland it divides into the 
internal maxillary 13 ' and 
temporal. 1 * 

Superior thyroid, 5 
arises near the root of the external carotid and is its first branch ; 
it pursues a curved course downwards and is distributed to the thy- 
roid gland, after giving off a laryngeal branch. (Fig. 116.) 




142 INTERNAL MAXILLARY. 

Lingual,* ascends obliquely from its origin, which is just above 
the superior thyroid. It penetrates the hyoglossal muscle just 
above the cornu of the hyoid bone, and then courses between the 
muscles of the tongue, giving off the dorsalis linguae, sublingual and 
ranine branches. The ranine reaches the tip of the tongue. 

Facial.' 1 — This arises above the lingual, is tortuous, becomes im- 
bedded in the submaxillary gland, and then passes over the lower 
jaw, in front of the insertion of the masseter muscle, and gives off 
several branches to the face. 

Sub-mental, arises from the last, and supplies the chin. 

Masseteric, also arises from the facial, and is distributed to the 
masseter muscle. 

Inferior labial, is spent upon the integuments and muscles be- 
tween the chin and the lip. 

Superior and inferior coronary, surround the lips and mouth. 
The remainder of the facial artery is distributed by a branch upon 
the side of the nose and one to the inner angle of the eye, where it 
anastomoses with the ophthalmic. 

Inferior pharyngeal** arises near the bifurcation of the carotid, 
or from the external carotid, and is distributed to the pharynx. It 
often gives off the posterior meningeal, which enters the cranium 
through the posterior for amen lacerum. 

Mastoid? — This branch is irregular and uncertain in its origin, 
and supplies the muscles and glands of the neck. 

Occipital? arises from the external carotid a little below the 
facial, forming a loop with the hypoglossal nerve : it is distributed 
upon the muscles and integuments upon the back of the head, anas- 
tomosing with the temporal and its fellow. 

Posterior auricular, 1 ^ arises from the external carotid, ascends 
obliquely backwards, beneath the parotid gland, and passing between 
the external meatus and mastoid process, is distributed upon the in- 
teguments. A branch of it, called stylo-ma stoid, enters the stylo- 
mastoid foramen. 

TransversaMs faciei. 11 arises from the carotid, and crossing the 
masseter muscle parallel with the duct of Steno, is distributed upon 
the face. 

The anterior, posterior, and middle temporal are the terminating 
branches of the temporal artery. The anterior is distributed upon 
the temple and side of the head. The posterior is distributed upon 
the integuments on the back of the head. The m id.d.le perforates 
the temporal fascia and supplies the temporal muscle. 

IHT1BIAI MAXILLARY. 

This 12 commences at the bifurcation of the external carotid, and 
pursues a very tortuous course, supplying the back portions of the 



ARTERIES OF THE BRAIN. 



143 




mouth and palate. At first it is 
horizontal, then ascending, it ter- 
minates in a horizontal course. 
Its branches are numerous, and 
are as follow : (Fig. 117.) 

Tympanic,' 7 is distributed to 
the tympanum through the Grla- 
serian fissure. . 

Meningea magna, 9 passes 
through the foramen spinale and 
becomes the middle artery of the 
dura mater. 

Meningea parva, 9 arises from 
the last or near to it, and is also 
distributed to the dura mater, 
having entered the cranium through the foramen ovale. 

Inferior dental, 10 descends to the posterior mental foramen, and 
supplies the teeth of the lower jaw, then emerging at the anterior 
mental foramen, anastomoses with the facial. 

Deep temporal. — These are two branches distributed to the tem- 
poral muscles. 

Pterygoid and Buccal. — These are muscular branches supplying 
the muscles and the lining of the cheek. 

Superior dental, or alveolar, or maxillary, 11 descends, and wind- 
ing round the tuberosity of the upper jaw, gives off branches to the 
molar teeth, antrum, and gums. 

Infra-orbital, 12 enters the orbit of the eye, and passes along the 
infra-orbital canal ; it sends branches to the teeth and integuments 
of the face. 

Superior palatine, 13 passes through the posterior palatine foramen, 
and supplies the mouth and palate. 

Superior pharyngeal, 15 supplies the upper part of the pharynx 
and the Eustachian tube ; from it arises the vidian. 16 

Spheno-palatine, 1 * enters the nose through the spheno-palatine 
foramen, and is distributed by branches to the mucous membrane 
of the nose. 

ARTERIES OF THE BRAIN. 

The arteries at the base of the brain are derived from the verte- 
brals and internal carotids. (Fig. 118.) 

The vertebral arteries 1 enter the cavity of the cranium through 
the foramen magnum occipitis, and coalescing, form a thick trunk 
called the basilar 6 Previous to their union are given off the ante- 
rior 2 and posterior* spinal arteries. The inferior cerebellar arises 
from the vertebral also. The basilar pursues its course along the 
median line of the pons varolii, giving off several branches in its 



144 



SUBCLAVIAN. 



Fig. 118. 




course. The principal 
being the superior cere- 
bellar' 7 and the posterior 

cerebral arteries. 8 

The posterior com- 
municating 9 joins the 
carotid 10 with the poste- 
rior cerebral. 

From the carotid, 
which enters through 
the carotid canal, are 
given off the ophthal- 
mic, 11 middle cerebral, 12 
and anterior cerebral 
arteries. 1Z The two an- 
terior cerebral arteries 
are connected by a 
transverse branch 14 call- 
ed the anterior commu- 
nicating artery and thus 
is formed the circle of 
Willis. These vessels 
are distributed to the 
pi a mater, and the sub- 
stance of the brain. 



SUBCLAVIAN. 

The subclavian 3 of the right side arises from the innominata, 1 and 

the subclavian of the left side from 
Fig. 119. the arch of the aorta. The right is 

shorter and more superficial than 
the left. The subclavian emerges 
from the thorax by passing over the 
first rib between the anterior and 
middle scaleni muscles. Its branches 
are numerous, and vary in their 
mode of origin. Some arise by a 
common origin, 8 called the thyroid 
axis. 

Vertebral, 6 is the first and largest 
branch of the subclavian. It passes 
through the foramina of the trans- 
verse processes of the six superior 
cervical vertebrae, and enters the 
cavity of the cranium through the 
foramen magnum occipitis. 




AXILLARY. 



145 



Fig. 120. 



Inferior thyroid? arises from the thyroid axis or the subclavian, 
and curves forwards and upwards behind the great vessels of the 
neck to supply the thyroid gland, giving off the ascending or super- 
ficial cervical. 9 

Superior intercostal,** arises from the subclavian, and descending, 
supplies the two upper intercostal spaces. It frequently gives off 
the profunda cervicis. 10 

Internal mammary™ is larger than the last, and entering the 
cavity of the thorax, descends within a few lines of the sternum, 
giving off branches to the diaphragm, thorax, and abdomen. 

Posterior or transverse cervical, 11 arises from the subclavian in an 
irregular manner, and winds round the root of the neck, in front 
of the brachial plexus and scalenus 
anticus muscle, until it reaches the 
base of the scapula, along which 
it descends, and supplies the muscles 
upon the back. The subclavian ar- 
tery, passing under the subclavius 
muscle, is afterwards called axil- 
lary. 

Profunda cervicis 10 arises from 
the subclavian or the superior inter- 
costal. It ascends the back of the 
neck between the complexus and 
semi-spinalis colli muscles. 

Supra-scapidar , or transversalis 
humeri. 12 — This usually arises from 
the thyroid axis, but sometimes from 
the axillary. It passes over the 
scapula, and supplies the muscles 
upon its dorsum, sending a small 
branch through the coracoid notch. 

AXILLARY. 

This artery may also be consider- 
ed as extending from the lower edge 
of the subclavius muscle to the 
lower margin of the tendon of the 
latissimus dorsi. 

External mammaries. — Usually 
are four in number, arising singly or together, from the axillary. 
They are the acromial thoracic, 11 distributed upon the shoulder, 
and sending a branch between the pectoralis major and deltoid 
muscles ; superior and inferior thoracic, 13 which are distributed 
upon the pectoralis and the serratus magnus muscles; and the 

13 




146 RADIAL. 

axillary thoracic, which is distributed to the fat and glands of the 
axilla. 

Scapular. 1 * — This is the largest branch of the axillary ; it passes 
along the external edge of the scapula, and gives off a large branch, 
called dorsal is scapulae, which anastomoses with the supra-scapular, 
on the dorsum of the scapula. 

Anterior and Posterior Circumflex, arise from the axillary, oppo- 
site the neck of the humerus. The anterior is small, and supplies 
the front of the joint ; the posterior is large, and passes backwards, 
supplying the joint and deltoid muscle. Sometimes it arises from 
the profunda major. 

BRACHIAL. 

The brachial artery extends from the axilla to the elbow joint, 
descending upon the inner edge of the coraco-brachialis and biceps 
flexor muscles, in company with the median nerve. (Fig. 120.) 

Profunda major, 15 arises from the brachial at its upper part, and 
passing between two heads of the triceps muscle, with the spiral 
nerve, supplies the external portion of the arm, and at the external 
condyle inosculates with the radial recurrent. 

Profunda minor, 16 is small, arises below the last, is distributed 
superficially about the internal condyle, and anastomoses with the 
ulnar recurrent. 18 

Nutritious artery, arises opposite the nutritious foramen of the 
humerus, which it enters to supply the bone. 

Anastomotic, 117 arises from the brachial just above the elbow, and 
winding round the internal condyle, anastomoses with the ulnar 
recurrent. (Fig- 121.) 

The brachial, passing under that portion of the brachial fascia 
which is connected with the tendon of the biceps, divides into the 
radial and ulnar, although this division may take place at any 
point between the arm-pit and elbow. 

E A D I A L. 

The radial 12 is more superficial than the ulnar. It descends the 
outer side of the arm, 12 between the tendons of the supinator radii 
longus and flexor carpii radialis. 

Radicd recurrent, l3 arises from the radial and inosculates with 
the profunda major. In its descent, the radial gives off numerous 
muscular branches, until it reaches the wrist, it then passes back- 
wards under the extensor tendons of the thumb. 

Superficialis voice, 14 is given off from the radial, and distributed 
upon the palmar surface of the thumb, joining the superficial arch. 

Dorscdis carpi, arising from the radial, is distributed upon the 
back of the wrist beneath the extensor tendons. 

Magna pollicis, one of the terminating branches of the radial, 
supplying the thumb. 



THORACIC AORTA. 



147 



Radialis indicts,^ 7 arises in con- 
nexion with the last, and is distributed 
upon the radial side of the forefinger. 

Palmar is profunda, or deep arch, 
another terminating branch of the ra- 
dial, which passes between the flexor 
tendons and bones of the metacarpus, to 
join the cubitalis manus of the ulnar. 

ULNAR. 

It passes 15 under the bellies of se- 
veral superficial muscles arising from 
the internal condyle, and descends the 
inner side of the arm, between the 
tendons of the flexor carpi ulnaris and 
flexor sublimis muscles ; then passes 
over the annular ligament of the 
wrist, to form the superficial arch. 
(Fig. 121.) 

Ulnar recurrent, 1 * arises from the 
ulnar near its commencement, and then 
winding under the internal condyle, 
anastomoses with the anastomotic. 

Interosseous, 19 arises from the ulnar 
opposite the tubercle of the radius, and 
divides into an anterior and posterior 
branch ; the anterior interosseous de- 
scending to the wrist in front of the 
interosseous ligament ; the posterior 
perforates the ligament, and is distribu- 
ted to the extensor muscles of the arm. 

Dorsalis manus, arises from the ulnar, and is distributed upon the 
back of the hand. 

Superficial arch, 16 is a continuation of the ulnar artery, immedi- 
ately beneath the palmar fascia. 

Cubitalis manus profunda, a branch of the ulnar, arising near the 
superficial arch; it joins the deep arch. 

Digital arteries. — These are three in number, and arise from the 
superficial arch. At the metacarpophalangeal articulation, they 
divide into the digito-radial and digito-ulnar, for each side of the 
finger. The ulnar side of the little finger is supplied by a distinct 
branch from the superficial arch. 

THORACIC AORTA. 

The Thoracic Aorta descends upon the left side of the vertebral 
column through the posterior mediastinum. 

Bronchial,™ vary in size and origin. Sometimes arising by a 




148 



ABDOMINAL AORTA. 



common trunk from the arch of the Aorta. They enter the root of 
each Inns, and supply its parenchymatous structure, glands, cVc. 

T^g. us: 

(Esophageal, 3 are from four to six in number, arising from the 
anterior conyexity of the aorta, to be distributed to the cesophagus. 

Intercostal.- 1 — These are ten in number on each side, arising from 
the posterior conyexity of the aorta. 

They supply the ten inferior intercostal spaces, the right being 
somewhat longer than the left. They are receiyed in the intercostal 
grooye upon the under edge of each rib, for two-thirds of its length. 

ABDOMINAL AORTA. 

The Abdominal Aorta commences at the hiatus aorticus of the 
diaphragm and terminates at the junction of the fourth and fifth 
lumbar vertebrae, in the iliacs and middle sacral. 

Ph. ren ic. ' — These are 
Fig- 122. two in number, one for 

each side of the dia- 
phragm, to which they 
are distributed • some- 
times they arise by a 
common trunk from the 
cceliac. 

I :'ac axis.' — A short, 
thick trunk about half an 
inch in length, giyen off 
opposite the junction of 
the last dorsal and first 
lumbar yertebne ; it di- 
vides into the gastric, he- 
patic, and splenic. 

Gastric, 3 is the small- 
est branch of the cceliac, 
and supplies the lesser 
curyature of the stomach. 
Hepatic,* enters the 
transyerse fissure of the 
liyer, and divides into two 
or three branches, before 
entering the substance of 
the liyer. It gives off the 
, which supplies the 
gall-bladder and the right 
gastro-epijploicj which 
supplies the right side of 
the greater curvature of 
the stomach. 




ABDOMINAL AORTA. 



149 



Splenic. — This is the largest "branch of the eoeliac. It is very tor- 
tuous, and passes transversely to the spleen over the upper edge of 
the pancreas ; from it are given off the vasa brevia and left gastro- 
epiploic arteries, supplying the left extremity and left side of the 
greater curvature. 

Superior mesenteric^ arises immediately below the eoeliac and is 
nearly as large. It passes beneath the pancreas and over the duo- 
denum, and descending towards the right side it forms a curvature, 
the convexity of which is to the left. (Fig. 123.) From it are given 
sixteen or twenty large branches, which form an arch; 16 from this 
arch are given off secondary branches to form a second arch, and from 
this a third is formed. From this last arch the branches are de- 
rived which supply the small intestines. From the superior mesen- 
teries are also given off three branches to the right side of the large 
intestine : ileo-colica 15 supplying the caecum and a portion of the 
ileum; colica dextra supplying the ascending colon, and colica 
media' 1 supplying the arch of the colon. 

Fig. 123. 




Capsular, 6 arise from the aorta or renal, and supply the supra-renal 
capsules. (Fig. 122.) 

13* 



150 



ABDOMINAL AORTA. 



Renal or Umulgent. 17 — These are of large diameter, though- not 
very long. They pass transversely to the kidney, and divide into 
several branches before entering it. The right is longer and more 
oblique in its course than the left, and is partly concealed by the 
ascending vena cava. (Fig. 122.) 

Spermatic™ — These are about the size of a large knitting-needle, 
arising from the aorta and sometimes from the renal. They are 
tortuous in their course and pass through the abdominal rings; after 
which they divide into several branches before reaching the testicles. 

In the female, they are distributed to the ovaries. 

Fig. 124. 




Inferior mesenteric, %1 arises from the aorta an inch above its bifur- 
cation. (Fig. 124.) It is about the size of a goose-quill, and gives 
off the superior left colic, 11 middle left colic, 13 and inferior left colic 
arteries, which supply the descending colon, and also the superior 
hemorrhoidal,™ which is distributed to the upper part of the rectum. 



INTERNAL ILIAC. 



151 



Lumbar. 8 (Fig. 122.) Arise on each side of the aorta, and are 
four or five in number ; they correspond with the intercostals of 
the chest, and supply the muscles of the loins and abdomen. 

Middle sacral. 12 — Is the termination of the aorta arising at its 
bifurcation into the iliacs. It descends along the median line of 
the sacrum. 

COMMON ILIAC. 

The aorta 1 divides into the iliacs at the lower part of the fourth 
lumbar vertebra. The iliac 9 descends obliquely outwards to the 
sacro-iliac articulation, being crossed by the ureter, and divides into 
the external* and internal iliac. 6 

Fig. 125. 




INTERNAL ILIAC. 



This is a short trunk, 6 descending in front of the sacro-iliac junc- 
tion into the cavity of the pelvis, and giving off numerous branches 
with great irregularity and variety from its two principal trunks, 
the gluteal 8 and ischiatic. 7 (Fig. 125.) 

llio-lumbar. t6 — Arises from the internal iliac or one of its prin- 
cipal trunks, ascends outwardly toward the crest of the ilium, and 
is spent upon the loins, anastomosing with the circumflex ilii. 

Obturator. i7 — May arise at various parts of the internal iliac, and 
passing forwards below the brim of the pelvis, escapes from it at 
the upper part of the thyroid foramen ; it is distributed by two 
branches upon the obturator and adductor muscles. Sometimes it 
arises from the epigastric. 

Lateral sacral. ,8 — This artery sends four branches through the 
anterior sacral foramina, anastomosing with the middle sacral. 30 

Gluteal. 19 — Is a continuation of the posterior trunk. It passes 
out of the pelvis at the upper part of the sacro-sciatic notch above 
the pyriformis muscle, and is distributed by two or three branches 
to the glutei muscles. 



152 



INTERNAL ILIAC. 



Vesical. l0 — Arises from the remains of the umbilical, 9 or from 
the internal iliac, and is spent upon the bladder. There is some- 
times an inferior vesical. 15 

Middle hemorrhoidal.* 3 — Is of variable size and origin. It is 
distributed to the rectum, vesiculfe seminales, and prostate gland. 

Ischiatic. u — Is the anterior of the two principal trunks of the 
internal iliac. It passes out of the pelvis through the sciatic notch, 
between the pyriformis muscle and great sacro-sciatic ligament. 
I: supplies the muscles on the floor of the pelvis and back of the 
thigh. 

Internal pudic. n — Arises from the last, previous to its emergence 
from the pelvis. It also escapes from the pelvis, and returns be- 
tween the sciatic ligaments ; ascending upon the ramus of the 
ischium and pubes, it supplies the penis and perineum. (Fig. 126.) 

Fig. 126. 




Lower hemorrhoidal. 10 — Arises from the internal pudic, 9 and is 
distributed upon the anus and rectum. There are sometimes two 
arteries. 

Transverse perineal. 11 15 — Arises near the eras of the penis, and 
runs across the transverse perineal muscles. It is cut in the lateral 
operation for stone. 

Urethro-bulbo.r. 1 * — Is given off from the pudic near its perforation 
of the triangular ligament, and enters the corpus spongiosum, which 
it supplies. 

Dorsalis Penis. — Ascends until it gets under the arch of the 
pubes, and then runs along the back of the penis. 

Cavernous. 14 — Another terminal branch which enters the corpus 
cavernosum. 



FEMORAL. 



153 



EXTERNAL ILIAC. 



This artery 3 extends (Fig. 125) from the sacro-iliac junction along 
the inner border df the psoas rnagnus muscle to the crural arch ; 
when it passes under Poupart's ligament it becomes the femoral.™ 

Epigastric* — Arises from the external iliac just behind Poupart's 
ligament, and ascends obliquely upwards and inwards, in the trans- 
versalis fascia, and between the two abdominal rings, whereby it is 
endangered in the operation for hernia. A branch of it supplies 
the cremaster muscle. 

Circumflex ilii, s arises from the external iliac opposite the epigas- 
tric, and ascends obliquely until it reaches the crest of the ilium, 
where it divides and supplies the muscles of the loins and abdomen. 
The last two arteries anastomose freely with the internal mammary 
and lumbar arteries. 

Fig. 127. 



FEMORAL. 



This artery commences at Poupart's li- 
gament, being a continuation of the exter- 
nal iliac. It passes spirally down the 
inner side of the thigh, and perforating 
the tendon of the adductor magnns 
muscle, becomes the popliteal. Its upper 
third is superficial, and upon the outer side 
of the femoral vein. Its lower two-thirds 
are covered by the sartorius muscle. 

Superficial artery of the abdomen, 2 arises 
from the femoral, just below Poupart's 
ligament, and ascends obliquely upon the 
integuments on the lower portion of the 
abdomen. It may be cut in the operation 
for inguinal hernia. 

External pudics. 15 ,8 — These are several 
branches, arising from the upper part of 
the femoral, and distributed to the integu- 
ments and glands of the groin. 

Profunda, 17 is almost as large as the 
femoral, from which it arises at about two 
inches below Poupart's ligament. It passes 
downwards and backwards between the 
adductor brevis and vastus internus mus- 
cles. 

External circumflex 13 is a branch of the 
profunda, and passes outwards between the 
rectus and cruraeus, to supply the upper 
part of the muscles of the thigh. 




154 ANTERIOR TIBIAL. 

Internal circumflex* is larger than the external, and supplies the 
muscles upon the inner side of the thigh, and gives off a perfo- 
rating artery. The perforating arteries are branches of the inter- 
nal circumflex and profunda, which perforate the adductor magnus, 
and supply the muscles upon the back of the thigh. 

Anastomotic, 19 6 arises from the femoral above its perforation of 
the adductor magnus tendon, and anastomoses with the articular 
arteries of the knee. 

POPLITEAL. 

This artery is a continuation of the femoral, and extends from 
the perforation in the adductor tendon, to its division into the ante- 
rior and posterior tibial below the knee. (Fig. 129.) 

Superior articular. 9 — These are two in number, one internal and 
one external, given off above the condyles, anastomosing with each 
other and the anastomotic artery. 

Inferior articular. — These are also external and internal, and 
supply the knee-joint below the head of the tibia. 

Middle articular. — Is small, and perforates the ligament of 
Winslow, to supply the interior of the joint. 

Gemellar. — These supply the heads of the gastrocnemius mus ■:■'.:-. 

POSTERIOR TIBIAL. 

This artery 11 u descends the back of the leg, under the muscles 
which form its calf, and nearer to the tibia than the fibula. (Fig. 
1280 

Peroneal or fibular, 1 * u arises from the posterior tibial, and di- 
vides into several branches, which are distributed upon the muscles 
arising from the fibula. 

As the posterior tibial approaches the ankle, it passes between 
the internal malleolus and the tendo Achillis into the sinuosity of 
the os calcis. 

ANTERIOR TIBIAL. 

This artery 10 (Fig. 129) perforates the interosseous membrane, 
at its upper part, and descends in front of it to the ankle. Its 
upper third 9 is situated between the tibialis anticus and extensor 
longus digitorum muscles ; below, it runs between the tibialis an- 
ticus and extensor proprius pollicis. In its course it gives off 
numerous muscular branches, and when it reaches the ankle 
becomes more superficial, being covered by the tendons upon the 
instep. 

Recurrent tibial,* ascends beneath the tibialis anticus, and anas- 
tomoses with the articular arteries of the knee-joint. 

Internal malleolar. " — Arises from the anterior tibial above the 
ankle-joint, and is distributed upon its inner side. 



ANTERIOR TIBIAL. 



155 



External malleolar. i7 — Arises below the last, and is distributed 
upon the outside of the ankle. 

Tarsal. 8 — Arises from the anterior tibial, and arches transversely 
across the tarsus, "beneath the extensor brevis digitorum muscle. 

Metatarsal. 1 * — Arches across the bases of the metatarsal bones, 
and gives off three interosseal branches, which supply the toes. 



Fig. 128. 



Fig. 129. 



Dorsalis hallucis. 15 — Is the terminating branch of the anterior ti- 
bial, and supplies the outer side of the great toe and the inside of 
the second toe. 

Pedal. 16 — This branch forms the communication between the 
anterior tibial and external plantar arteries. It descends to the sole 
of the foot, through the first interosseous muscle. 



u 



VEINS OF THE HEAD AND NECK. 



fig :::. 




through tht 



- : " 



- 



PIAJIAE. 

These arterie- 7 _ 12 )) are two in number, 
and are branches of the posterior tibial/-" which 
reaches the sole of the foot 
sinuosity of the os calcis. 

Zirnal plantar ~ — This is the larger of 
the two, and passing obliquely outwards upon 
the sole of the foot, it forms a deep arch 3 
above the muscles of the foot. From it are 
given off digital arteries for the supply of the 
interosseous spaces, and which, bifurcating 
into the external and internal branches, 
supply the toes. The external plantar ter- 
minates in the pedal artery. 

Internal plantar. 5 — This is a small artery, 
which passes along the inner border of the 
foot, and terminates in the digital artery of 
the great toe. 

VEINS. 
The veins return the blood to the heart. 
They are much more numerous than the ar- 
teries, and differ from them in having valves 
opening towards the heart. 
These valves are formed of two or three creseentic folds of the lining 
membrane, and give the veins a knotty appearance when injected. 
They are more numerous in the superficial vessels. 

The veins have three coats, but they are much thinner than 
those of the arteries; this deficiency, particularly in the middle 
elastic coat, gives them a flaccid appearance when empty, whereby 
they can be readily distinguished from arteries, which retain their 
cylindrical character. 

The superficial veins are more tortuous and irregular than the 
deep. The deep accompany all the arteries, with the exception of those 
of the lar ± -^: glass. There are two veins for each artery, and they 
are called vev.se comites, or satell':: 

>. .. sea are channels conveying venous blood, and lined by the 
internal coat of the veins. 

The distribution and anastomoses of the veins are much more 
irregular than those of the arteries. 




TEI.V3 01 THE HEAD AND NECK. 

The venous blood from the face is for the most part collected by 
veins accompanying the arteries, and which have the same name. 
The principal trunks, viz., the temporal, internal maxillary, and 



SINUSES OF THE DURA MATER. 



157 



Fig. 131. 



occipital, join to form 
a superficial vein of the 
neck, called external 
jugular. 

External jugular? — 
Receives the blood from 
the temporal, 8 occipital, 5 
and internal maxillary. 
It commences at the lower 
edge of the parotid gland, 
and descends the neck su- 
perficially, being merely 
covered by the skin, pla- 
tysma myoides muscle, 
and superficial fascia. Its 
course is towards the 
middle of the clavicle. 
It crosses obliquely the 
sterno - cleido - mastoid 
muscle, and empties into 
the subclavian, outside of 
the origin of this muscle. 
It is frequently selected 
for bleeding in children. 

Internal jugular. " — 
This vein is the largest 
of the neck. It receives 
the blood from the lateral 
sinus of the dura mater, and also from some superficial veins. 

The facial vein 16 empties into the internal jugular, and also forms 
a communication 4 between it and the external jugular. The inter- 
nal jugular descends the neck in a sheath with the carotid artery, 
being on the outer side. The par vagum nerve is in the same 
sheath and between the vessels. This vein empties into the subcla- 
vian on the inner side of the origin of the stern o-cleido-mastoid 
muscle. This junction forms the vena innominata. 




SINUSES OF THE DURA MATER. 

These are channels between the laminae of the dura mater, which 
remove the blood from the brain. (Fig. 133.) 

Superior longitudinal sinus. 1 — This is a triangular channel, com- 
mencing at the foramen eascum by a small vein from the nose, and 
gradually increasing in size by the junction in an oblique manner, 
of the veins of the pia mater. 2 It forms an arch in the median line 
of the vault of the cranium, which terminates at the internal occi- 
pital cross in an enlargement called Torcular Herophili. 7 

14 



158 



SINUSES OF THE DURA MATER. 




Fig. 132. Inferior longitudinal 

__ / sinus.- — This is situated 

in • the inferior margin 
of the falx cerebri ; it 
empties into the straight 
sinus at the interior edge 
of the tentorium. 

Straight, or Fourth 
sinus. 5 — It reaches from 
the junction of the in- 
ferior longitudinal sinus 
to the torcular Hero- 
phili, in the median line 
of the tentorium, where 
it is joined by the falx 
cerebri. 

Venas Galenic — These 
veins are in the velum 
interpositum ; they frequently unite into a trunk called vena azvgos, 
before entering the straight sinus. 

Lateral sinuses. 11 — These corn- 
Fig. 133. mence at the torcular Herophili, are 
oval-shaped channels, and pursue a 
curved course over the occipital, pa- 
rietal, and temporal bones, until they 
reach the posterior foramen lacerum, 
where they emerge, and form the 
commencement of the internal jugular 
vein. 7 In their course they receive 
blood from several other sinuses. 
(Fig. 133.) 

Cavernous sinuses, 2 are venous cells 
on either side of the sella turcica, 
containing a spongy structure; into 
them empty the ophthalmic veins/ 
and through them pass the internal 
carotid artery and the sixth nerve. 

Circular sinus. 3 — It surrounds the 
pituitary gland in the sella turcica, 
and communicates upon each side 
with the cavernous sinus. 

Superior petrosal sinus. 6 — This is 
a small sinus, running along the edge 
of the petrous portion of the temporal bone, and reaches from the 
cavernous to the lateral sinus. 

Inferior petrosal sinus. 4 — Extends from the cavernous sinus on 




VEINS OP THE UPPER EXTREMITY. 



159 



Fig. 134. 



each side, along the inferior margin of the petrous portion of the 
temporal bone, and opens into the lateral sinus near its exit from 
the cranium. 

Anterior occipital sinus. 5 — It passes transversely across the basi- 
lar process of the occipital bone, connecting the two inferior pe- 
trosal sinuses. 

Posterior occipital sinus. 9 — This is in the inferior edge of the falx 
cerebelli, descending from the torcular Herophili j when it reaches 
the foramen magnum, it bifurcates and empties into the lateral sinus 
upon each side. This communication is not represented in the 
diagram. 

The venous blood from the channels in the diploic structure 
empties into the sinuses at the base of the cranium. 

Emissaries of Santorini, are small veins passing through minute 
foramina of the bones of the cranium and forming a communication 
between the vessels of the scalp and the sinuses of the brain. 

VEINS OF THE UPPER EXTREMITY. 

The superficial veins of the upper extremity are readily seen be- 
neath the skin ; the deep veins have the usual arrangement of the 
vence comites. The superficial veins are the following : 

Cephalic. 2 — This originates upon the 
thumb by a branch called cephalica polli- 
cis, and also upon the back of the hand; 
ascending upon the radial side 1 of the fore- 
arm, it is joined at the elbow by the median 
cephalic. It pursues its course along the 
outer side of the biceps, and entering a fis- 
sure between the pectoralis major and deltoid 
muscle, it empties into the subclavian vein 
under the clavicle. It sometimes communi- 
cates with the external jugular. 

Basilic,' 7 commences with the vena salva- 
tella of the little finger, and receiving large 
branches 3 4 upon the ulnar side of the fore- 
arm, it is joined at the elbow by the median 
basilic. It then ascends the arm along the 
inner edge of the biceps muscle, and about 
its middle it joins the vense comites to form 
the axillary vein. 

Median. 8 — This collects the blood from 
the anterior face of the fore-arm, and near 
the elbow communicates 9 with the deep 
veins. It afterwards divides into the median 
oasilic'' 1 and median cephalic.™ The latter 
is the smaller of the two, and under it pass 




160 



INFERIOR OR ASCENDING VENA CAVA. 



branches of the external cutaneous nerve. 14 A branch of the in- 
ternal cutaneous nerve 13 l3 passes over the median basilic, and may 
be cut in- bleeding. 

Axillary. — It is formed by the junction of the basilic with the 
venae comites of the brachial artery. It lies in front of the artery, 
and at the subclavius muscle terminates in the subclavian vein. 

Subclavian. — This is a continuation of the axillary. It passes 
under the clavicle and over the first rib to join the internal jugular 
and form the vena innominata. It lies in front of the artery, and 
is separated from it while passing over the first rib by the scalenus 
anticus muscle. 



SUPERIOR OR DESCENDING VENA CAVA. 

The veins which form the descending cava 1 are the right and left 
venae innominata. 
Fig. 135. Eight Innominata, 3 is about an inch 

and a quarter in length, and is formed 
by the junction of the internal jugular" 
and subclavian 4 veins. At this junc- 
tion it receives the right thoracic duct. 
It descends superficially and obliquely 
in front of the arteria innominata to 
join its fellow. 

Left Innominata? — This is much 
longer than the right, and is formed 
in the same manner. It receives 
at its commencement the left tho- 
racic duct. It passes horizontally 
across the chest in front of the large 
vessels arising from the arch of the 
aorta, and behind the first bone of the 
sternum. It is frequently called the 
transverse vein. With its fellow, it 
forms the descending vena cava. 

The descending vena cava is about 
three inches in length, and descends 
perpendicularly to enter the upper part 
of the right auricle. 

INFERIOR OR ASCENDING VENA 
CAVA. 

This is formed by the junction of 
the iliac veins between the fourth and 
fifth lumbar vertebrae. It ascends 8 upon 
the vertebral column to the right of the 
aorta, and in its course receives the 
lumbar, right spermatic, renal, and he- 




PORTAL VEIN. 



161 



patic veins ; it passes through the fissure of the liver between the 
right lobe and the lobulus Spigelii, and then enters the foramen quad- 
ratum of the diaphragm, to terminate at the right auricle of the heart. 

Spermatic veins. — These originate in the vasa pampiniformia of 
the cord and testicle. The right 13 empties into the ascending cava, 
and the left 14 into the left renal. 

Renal or Emulgent. — These are large, and return the blood from 
the kidney to the ascending cava. The right 15 is much shorter than 
the left. The left passes in front of the aorta. 

Hepatic. i6 — These convey the venous blood from the liver by 
three large branches, which open at its posterior notch, into the 
ascending cava, as it passes through the fissure in the liver. 



VENA AZYGOS. 



This vein 17 commences in the lumbar regions, and being joined 
by the intercostal veins of the right side, it winds around the root 
of the right lung, and empties into the descending cava. It also 
receives the right bronchial and the right superior intercostal veins. 

Vena hemiazygos. i8 — This is formed by the lower intercostal and 
superior lumbar veins, and passes in front 20 of the vertebral column to 



join the vena azygos. 

Left superior in- 
tercostal. 21 — This re- 
ceives the blood 
from the six superior 
intercostals, and the 
left bronchial vein; 
it forms a communi- 
cation between the 
left subclavian and 
azygos veins. 

The above veins 
form a communica- 
tion between the 
venous blood of the 
upper and lower ex- 
tremities, indepen- 
dent of its mingling 
in the heart. (Fig. 
135.) 

PORTAL VEIN. 

This vein 9 col- 
lects the blood from 
all the chylopoietic 
viscera, and enter- 



Fig. 136. 




14* 



162 



LYMPHATICS. 



ing the transverse fissure of the liver, divides into the right and left 
sinnses. In its course it receives the inferior 1 and superior 6 mesen- 
teric veins, splenic, 3 and gastric ; 5 and then is included with the 
hepatic artery, 10 and the ductus communis choledochus 11 in the cap- 
sule of G-lisson. The veins forming the portal vein have no valves. 

Vesical plexus. — This plexus surrounds the neck of the bladder, 
seminal vesicles, prostate gland ; its blood passes into the internal 
iliac vein. 

Uterine plexus. — Surrounds the uterus and vagina, and empties 
as the vesical does. 

Hdemorrlioidal veins. — Surround the rectum, and empty into the 
inferior mesenteric and internal iliac veins. 



VEINS OF THE LOWER EXTREMITY. 

The superficial veins of the lower extremity are two in number. 



Fig. 137. 




Internal sapliena . — Commencing upon 
the inside of the foot and ankle it ascends 
upon the inside of the leg, and passing 
behind the internal condyle, it traverses 
the superficial fascia of the thigh and 
c enters the femoral vein at the saphenous 
opening of the fascia lata. 

External saphena. — Commencing upon 
the outer and posterior parts of the foot, 
it ascends upon the back of the leg and 
enters the popliteal vein above the knee. 

Popliteal, is formed by the junction of 
the deep veins accompanying the anterior 
and posterior tibial arteries. It is super- 
ficial to the popliteal artery. 

Femoral vein. — The femoral vein com- 
mences at the opening in the adductor 
magnus tendon, and ascends the thigh 
in company with the femoral artery. It 
passes under Poupart's ligament, to be- 
come the external iliac vein. It lies 
upon the inside of the femoral artery, 
as it passes over the pubes, and forms 
the outer boundary of the crural ring. 

LYMPHATICS. 

Lymphatics are small, pellucid ves- 
sels found in almost all portions of the 
body. They are exceedingly numerous, 
and found most constantly in company 
with veins. 

They enter the lymphatic glands, 



NERVOUS SYSTEM. 163 

which are most numerous in the neck, groin, axilla, loins, and mesen- 
tery, and then emerge from them. 

The lymphatics of the intestine, commence in the villi of the 
intestine; they are often called lacteals, and contain the chyle. 

They iiave three coats, like arteries, and present a knotted ap- 
pearance when distended, owing to the existence of sinuses and 
valves. 

Left thoracic duct. 13 — This is the principal lymphatic vessel of the 
body ; it receives the contents of the lymphatics or absorbents of the 
lower extremity, by an enlargement called receptacidum chyli 12 
(Pecquet) ; and entering the thorax through the hiatus aorticus, it 
traverses the thorax through the posterior mediastinum in front of 
the vertebral column, and between the vena azygos 10 and aorta. 3 
After reaching the fourth dorsal vertebra it ascends obliquely to the 
left side, and enters 14 the junction 9 of the left subclavian and the 
internal jugular veins. 

Right thoracic duct. ' 5 — It is a short trunk, formed by the union 
of the lymphatics of the right side of the head and neck, and right 
upper extremity. It terminates at the junction of the right sub- 
clavian in the right internal jugular vein. 



SECTION VI. 
NERVOUS SYSTEM. 

The principal divisions of the nervous system are the Brain, 
Spinal Marrow, and Nerves. 

The tissue of this system is included in membranes or sheaths, 
and consists of two differently coloured pulpy materials; one of 
which is the white or medullary, and the other the gray, cortical, 
or cineritious. 

The white or medidlary structure is fibrous; in the centre of each 
fibre or tubule is a stripe called the cylinder axis of Purhinje. 

The gray is more vascular, and is vesicidar in its structure. 
These vesicles contain a nucleus with a nucleolus. They are soft, 
and of a yellow or brownish colour. 

All ganglia and nervous centres consist of a mixture of white 
fibres and gray globules. (See " Physiology. ") 

The sheath of the nerves is called the neurilemma-, and the in- 
ternal material neurine. 

An anastomosis is the interchange of fasciculi between two 
trunks; each fasciculus remaining unaltered by, although in con- 
tact with, another. 



161 



MEMBRANES OF TEE SPINAL MARROW. 



A plexus is a combination of anastomoses into a network. 

Pacinian corpuscles are small elliptical bodies, found attached to 
the ulnar and digital nerves. They are of a. dull white colour, or 
opalescent, and about two-thirds of a line in length. 



MEMBRANES OP THE SPINAL MARROW. 



Fig. 138. 



Fig. 139. 




c 



The spinal marrow has 
three coverings. The dura 
mater is a white fibrous 
membrane, and is external. 
It is continuous with that 
of the brain, and, investing 
the spinal marrow loosely, 
terminates at its inferior ex- 
tremity in a pointed cul-de- 
sac. It does not adhere 
closely to the bony canal, 
except at the intervertebral 
foramina, where it affords 
sheaths for the nerves. Be- 
tween it and the walls of the 
bony canal is a quantity of 
loose cellular tissue infil- 
trated with fat and serum. 

The arachnoid is the mid- 
dle covering. This is a se- 
rous membrane, investing 
the spinal marrow, and lining 
the inner surface of the dura 
mater, to which it gives a 
smooth, polished appear- 
ance. It is extremely thin 
and transparent, and desti- 
tute of red blood-vessels. 

The jpia mater is the im- 
mediate covering. This is 
a cellular membrane, con- 
sisting almost entirely of 
vessels. It terminates in 
a round cord-like process, 
which reaches from the end 
of the spinal marrow to the 
bottom of the canal, and 
is concealed in the roots of the nerves which constitute the cauda 
equina. 



>j 



I 



MEMBRANES OF THE BRAIN. 165 



SPINAL MARROW. 



The spinal marrow is the medullary column included in the 
spinal canal of the vertebrae. It is cylindrical, and reaching from 
the atlas, ^terminates in a point at the first or second lumbar ver- 
tebra. It is flattened anteriorly and posteriorly, and has an enlarge- 
ment in the neck and loins. It is divided longitudinally into sym- 
metrical portions, by an anterior and a posterior fissure. The 
anterior 3 fissure is broad and shallow; the posterior 3 is deep and 
narrow. Each half is divided unequally by a lateral fissure ) the 
anterior column being the larger. 1 

A transverse section of the spinal marrow exhibits the arrange- 
ment of its medullary and gray matter. The medullary matter is 
external, and the gray, in this section, resembles two crescents 
united by a commissure. 

The posterior horns 4 of the crescent extend to the surface in the 
lateral fissure, in which originates the posterior 6 roots of the nerves. 

From the sides of the spinal marrow proceed 30 pairs of nerves, 
each originating by two roots ; the anterior from the anterior column, 
and the posterior from the lateral fissure, where they connect with 
the posterior horns. The posterior root is the larger, and upon it 
is a ganglion, which is in the ~. v ^^ 

invertebral foramen, beyond 
which the two roots unite. 
These two roots are separated 
by the lig amentum denticu- 
latum, a pointed process of pia 
mater, which contains between 
its laminae a good deal of yellow fibrous tissue. 

MEMBRANES OE THE BRAIN. 

The brain has three membranes, of which the most external is 
the dura mater. It is of the same structure as the dura mater of 
the spinal cord, composed almost entirely of white fibrous tissue. It 
consists of two laminae, which are only separate at the points where 
the sinuses exist. 

It adheres firmly to the bones of the cranium, particularly to 
those at the base of the skull. The internal lamina forms several 
processes. The falx cerebri is a fold of the internal lamina, reach- 
ing in the median line from the crista galli to the tentorium, and 
separating the two hemispheres of the brain. The tentorium is an- 
other fold, stretched horizontally, and also of a crescentic shape, 
separating the cerebrum from the cerebellum. The falx cerebelli 
is a smaller fold, reaching from the internal occipital cross to the 
foramen magnum, and separating the lobes of the cerebellum. 

The arachnoid is the serous membrane covering the brain, and 




166 CEREBRUM. 

lining the inner surface of the dura mater. It is thin and trans- 
parent. 

The pia mater is a vascular covering consisting of arteries and 
veins united by a small quantity of cellular tissue. It passes down 
in the fissures, between the convolutions, so as to invest them com- 
pletely. The dlands of Pacchioni are usually small and white gra- 
nulations, but sometimes are very large, especially in old persons. 
They are usually found along the margin of the longitudinal fissure, 
and sometimes produce absorption of the dura mater. 

THE BRAIN. 

The brain consists of four principal parts : Medulla Oblongata, 
Pons Varolii, Cerebrum, and Cerebellum. 

MEDULLA OBLONGATA. 

This is the upper part of the spinal cord ; it is conical in its shape, 
and extends from the atlas to the pons Varolii. It is divided by the 
anterior and posterior fissures symmetrically, and each half consists 
of three different parts. 

Corpus pyramidale. — This is a narrow, cylindrical portion, re- 
sembling a cord, and situated in front. It communicates freely with 
its fellow, by a decussation of their fibres, about one inch from the 
pons. 

Corpus olivare. — This is an oval, convex mass, behind and above 
the corpus pyramidale, from which it is separated by a fissure. It 
is about half an inch in length. A section of it exhibits an arrange- 
ment of cineritious matter called corpus fimbriatum. 

Corpus restiforme is the posterior division of each lateral column, 
and is separated from the corpus olivare by a groove. Between it 
and its fellow is a continuation of the posterior fissure called cala- 
mus scriptorius, across which pass transverse fibres of medullary 
matter, giving origin to the auditory nerve. 

PONS VAROLII. 

This is formed of medullary matter, and is cuboidal in shape. 
Externally, the fibres are transverse ; internally, they are longitu- 
dinal, being a continuation of those of the medulla oblongata. It 
is situated in front of the medulla oblongata, and rests upon the 
basilar process of the occiput. From it proceed four crura. 

CEREBRUM. 

The cerebrum is an oval mass, weighing from three to four pounds, 
and divided into two hemispheres by the superior longitudinal 
fissure. Each hemisphere consists of an anterior, middle, and pos- 
terior lobe. The anterior and middle lobes are separated by the 
fissure of Sylvius. The division between the middle and posterior, 



CEREBRUM. 167 

is an imaginary line in front of the anterior edge of the cerebellum. 
The surface presents a number of gyri } or convolutions, each sepa- 
rated by deep sulci, or fissures. The interior of each hemisphere is 
medullary, and the surface of each convolution is cineritious for the 
depth of one or two lines. 

Island of Rett is a cluster of radiated convolutions in the fissure 
of Sylvius. 

Crura Cerebri, are two thick, cylindrical white cords, which 
diverge from the anterior border of the pons, and their fibres termi- 
nate in the hemispheres of the brain. In a triangular space between 
them, is a layer of medullary matter called the locus perforatus. 

Eminent ise Mammillares, are two white, globular bodies, about 
the size of a pea, situated between the crura of the brain, and in 
front of the locus perforatus. 

Tuber Cinereum, is a soft, gray mass, in front of the eminentiae 
mammillares, and behind the chiasm of the optic nerves. 

Infundibulum, is a hollow, conical body, of a reddish colour, with 
its base upon the tuber cinereum, and its apex attached to the pitui- 
tary gland. 

Pituitary gland, is a vascular mass of a light colour, situated in 
the sella turcica. It consists of two lobes. 

Corpus Callosum, is a white, arched band, seen at the bottom of 
the longitudinal fissure, forming a commissure between the two 
hemispheres. It is three inches and a half long, and about an inch 
broad. Its fibres are for the most part transverse, and consist of 
medullary matter, with the exception of a few, which pass longitu- 
dinally, and are called the raphe. 

Septum Lucidum, is a vertical partition, consisting of two lami- 
nae, and separating the lateral ventricles. Its upper edge is in 
contact with the corpus callosum, and its lower with the fornix. 

Fornix. — It is a triangular, medullary arch, whose base is con- 
tinuous with the corpus, callosum posteriorly, and whose apex 
divides into two crura, which terminate in the eminentia mammil- 
lares; its under surface is termed lyra. Under these crura is the 
foramen of Monro, by which the third and two lateral ventricles 
communicate. 

Velum Interpositum, is a triangular reflection of pia mater, im- 
mediately under the fornix; its edges contain a plexus of veins 
called plexus choroides. 

Pineal Gland, is a small, reddish-gray, conical body, situated 
upon the tubercula quadrigemina, and connected by two crura 
with the optic tubercles. 

Tubercula Quadrigemina are four prominences situated over the 
junction of the pons and crura cerebri. Under them is a passage 
called aqueduct of Sylvius, or iter e tertio ad ventricidum quartum. 

Corpus Striatum, a gray mass of an oblong shape, situated in 
the lateral ventricle on either side. It is medullary within. 



168 CEREBELLUM. 

Thalamus Opticus, is an oval, convex mass, behind the corpus 
striatum on each side. It consists of a mixture of medullary and 
gray matter, and has three prominences called corpora geniculata, 
one on either side, and one in front. It is connected with its fellow 
by some cineritious substance, called the soft commissure. 

Taenia Striata, is a thin edge of medullary matter, in the groove 
between the corpus striatum and thalamus opticus. 

Hippocampus major, is a scroll extending into the inferior cornu 
of the lateral ventricle, the extremity of which resembles a foot, and 
is called the pes hippocampi. 

Corpus Fimhriatum, or Taenia Hippocampi, is a thin edge of 
medullary matter upon the concave side of the hippocampus major; 
beneath which is a layer of cineritious matter, having a serrate 
appearance, and called the fascia dentata. 

Hippocampus Minor, or Ergot, resembles a cock's spur ) is a 
conical elevation pointing backwards into the posterior cornu. 

Ventricles of the Brain. — These are five in number. They are 
called the right and left lateral, the third, fourth, and fifth ventricles. 

Lateral ventricles exist in each hemisphere, and contain the corpus 
striatum and thalamus opticus. Each communicates with the third 
and its fellow by the foramen of Monro, being separated partially 
by the septum lucidum ; the roof is formed by the corpus callosum. 
It contains three angular depressions called cornua; the anterior 
contains nothing ; the posterior, the hippocampus minor ; and the 
inferior, the hippocampus major. 

The third ventricle is the space between the thalami optici. Its 
roof is formed by the velum interpositum and fornix, and its floor 
by the locus perforatus and the tuber cinereum. It is traversed in 
front by the anterior commissure, a medullary cord extending 
between the corpora striata, and by the posterior commissure, 
which extends transversely between the thalami optici.' It com- 
municates with the lateral ventricles by the foramen of Monro, and 
with the fourth by the aqueduct of Sylvius. 

The fourth ventricle is situated between the pons Varolii, cerebel- 
lum, and medulla oblongata. Its floor is the calamus scriptorius, 
and its roof is the valve of the brain. Laterally, it is limited by 
the pia mater and the arachnoid. It communicates with the third. 

The fifth ventricle is situated between the laminae of the septum 
lucidum. It does not communicate with the other ventricles. 

CEREBELLUM. 

This constitutes about one-sixth of the brain, and is contained 
between the occiput and tentorium. It is oblong and flattened : its 
greatest diameter being transverse. It is composed of white and 
gray substances, the latter of which is external, and apparently 
arranged in laminse. It is divided by a longitudinal fissure into 
two lobes j the superior part of which fissure contains a ridge called 



CRANIAL NERVES. 169 

vermis superior, in advance of which is an elevation called monticu- 
lus. In the inferior part of this fissure is a smaller ridge called the 
vermis inferior. 

At the root of. the crura cerebelli are two small protuberances ; 
the one Ijelow it, in the erect position, is the lobulus nervi pneumo- 
gastrici, and the other the lobulus amygdaloides. 

The valve of the brain is a thin ivhitc lamina, extending from the 
inferior surface of the cerebellum to the corpora restiformia. 

Arbor vitse, a section of either lobe of the cerebellum, presents 
an arborescent arrangement of the medullary matter. 

Corjms Dentatum, or Rhomboideum, is a name applied to a gray 
mass with serrated edges, in the trunk of this medullary tree. 

CRANIAL NEEVES, 

These are nine in number, and are so called from their emerging 
through the foramina, at the base of the cranium. They are desig- 
nated by their function, as well as numerically. Their origin is as 
follows : 

1st. Olfactory. — Arises by three roots, which coalesce in the fis- 
sure of Sylvius. 

2d. Optic. — Arises from the thalamus opticus and the tubercula 
quadrigemina." 

3d. Motor Oculi. — Arises from the cms cerebri. 

4th. Patheticus. — Arises from the valve of the brain. 

5th. Trifacial. — Arises from the superior and posterior part of 
the pons Varolii. 

6th. — Motor Externus. — Arises from the corpus pyramidale. 

7th. Facial and Auditory. — The facial or portio dura arises in 
a groove between the corpus olivare and corpus restiforme near the 
pons Varolii. The auditory ox portio mollis arises from transverse 
striae upon the calamus scriptorius. The portio intermedia of the 
7th arises in the corpus restiforme, and may be considered as the 
posterior or sensitive root to the facial. 

8th. Pneumogastric, glossopharyngeal, and spinal accessory. — 
The first two arise by filaments from the fissure between the corpus 
olivare and the corpus restiforme ; and the last arises from the spi- 
nal cord by a series of slender roots, as low down as the fourth or 
fifth cervical vertebra. 

9th. Hypoglossal. — Arises in the fissure between the corpus py- 
ramidale and corpus olivare. 

The cranial nerves may be divided into three classes, according 
to their function, viz. : — Nerves of special sense, including the 1st, 
2d, and the auditory branch of the 7th. Nerves of motion, includ- 
ing the 3d, 4th, 6th, facial branch of the 7th and 9th. Compound 
nerves, comprising the 8th and 5th. 

15 



170 



CRANIAL NERVES. 



The distribution of the cranial nerves — 

1st. Olfactory. — It has a large, soft bulb, which rests on the cri- 
briform plate of the ethmoid bone, and sends filaments through its 
foramina to the Schneiderian membrane. 

2d. Optic. — Forms a chiasm with its fellow, and enters the globe 
of the eye through the foramen opticum, to join the retina. It is a 
flattened cord. 

3d. Motor Oculi. 3 — Passes through the external wall of the ca- 
vernous sinus to escape at the 
sphenoidal foramen, and then 
is distributed upon the mus- 
cles of the eyeball, with the 
exception of the superior 
oblique and external rectus. 
It sends a branch to join the 
ophthalmic ganglion, from 
which proceed the ciliary 
nerves, 8 which supply the 
iris. 

4th. Pathetic. — Passing 
through the external wall of 
the cavernous sinus, and 
through the sphenoidal fora- 
men, it is distributed upon 
the superior oblique muscle 
of the eyeball. It is the 
smallest cranial nerve. 
5th. Trifacial. — The trifacial or trigeminus is the largest of the 
cranial nerves, and has a fibrous appearance. It resembles the spi- 
nal nerves in arising by two roots, which can be traced into the 
anterior and posterior columns of the spinal marrow, and also in 
having a ganglion upon its posterior and larger root. 

This ganglion is called Casserian, and rests upon the depression 
upon the anterior portion of the petrous portion of the temporal 
bone. From it proceed three large branches, called ophthalmic, 
superior maxillary, and inferior maxillary nerves. The first and 
second branches confer sensibility on the structures on which they 
ramify ; but the third receives the motor filaments of the anterior 
root, and, therefore, confers motion as well as sensibility to the 
structures upon which it is distributed. 

The ophthalmic 6 passes out through the sphenoidal foramen into 
the orbit by three branches, the nasal, frontal, and lachrymal. The 
nasal 11 gives off the internal nasal, which enters the cranium 
at the anterior ethmoidal foramen, and then goes through the 
cribriform plate into the nose ; and also a branch (ramus cilia- 
ris) to the lenticular or ophthalmic ganglion. It is distributed 




CRANIAL NERVES. 



171 



Fig. 142. 




to the muscles of the orbit, 
eyelids, and conjunctiva. The 
frontal 3 divides into two 
branches, and is -spent upon the 
integumsnts and muscles of the 
forehead ; one branch goes 
through the supra-orbitary fora- 
men. The lachrymal 10 branch 
supplies the lachrymal gland, 
and the contiguous portions of 
the orbit. 

The superior maxillary" 1 passes 
through the foramen rotundum, 
and then enters the pterygo-max- 
illary fossa. 20 A large branch 
called infra orbital 16 traverses 
the infra-orbital canal, and 
emerges at the infra-orbital fora- 
men 19 to supply the face; giving 
off the dental nerves 1 * 17 in its 
course. The pterygopalatine 
branch, or branches, join the 
ganglion of Meckel'm the pterygo- 
id axillary fossa, from which proceed the spheno-palatine branches, 
which enter the nose through the spheno-palatine foramen ; one of 
these branches is long, and called naso-palatine, which joins its fellow 
at the ganglion of Cloquet in the foramen incisivum; the posterior 
palatine descends from the ganglion through the posterior palatine 
foramen, and is distributed to the palate and fauces ; the vidian, or 
pterygoid, or recurrent, 21 passes backwards from the ganglion 
through the pterygoid foramen, and divides into two branches, 
called superficial and deep petrous. The superficial petrous enters 
the hiatus Fallopii, and passing between the smaller bones of the 
ear, emerges at the Grlaserian fissure under the name of chorda 
tympani, which joins the submaxillary ganglion. The deep petrous 
enters the carotid canal, and joins the ganglion of Laumonier, 
which was formerly considered the origin of the sympathetic nerve. 

The inferior maxillary* is the largest branch of the 5th 
pair. It is composed of filaments from the Casserian ganglion, and 
of the anterior or motor root of the tri-geminus. It emerges from 
the cranium through the foramen ovale, and soon divides into two 
principal trunks which are separated from each other by the exter- 
nal pterygoid muscle. The external trunk is composed mostly of 
the motor filaments, and splits into five branches, which are distri- 
buted to the masseter, buccal, pterygoid, and temporal muscles. One 



172 



CRANIAL NERVES. 



of the temporal branches perforates the temporal fascia and commu- 
nicates with the auricular and facial nerves. The internal trunk 
gives off three branches, viz., the gustatory, superficial temporal, 
and inferior dental. 

The gustatory, passes between the pterygoid muscles, and then 
curves forward above the sublingual gland and beneath the mylo- 
hyoid muscle and parallel to the stylo-glossus muscle. — It accompa- 
nies the Whartonian duct, and is distributed to the papilla and mu- 
cous membrane upon the sides and tip of the tongue. 

The chorda tympani nerve joins it near the condyle of the lower 
jaw, and parts from it near the angle, to join the submaxillary gan- 
glion, whose branches pass in the submaxillary gland. 

The superficial temporal, or auriculotemporal, often commences 
by two roots, between which passes the meningea magna artery. 
From it proceed several branches, to the parotid gland, to the joint, 
to the external ear, and to the side of the head, in company with 
the branches of the temporal artery. 

The inferior dental descends between the pterygoid muscles, and 
enters the posterior mental foramen after having given off the mylo- 
hyoidean branch to the muscle of the same name. It then runs 
along the canal in the lower jaw, supplying the teeth, and then 
sends a branch through the anterior mental foramen, which is dis- 
tributed upon the chin. 



Fig. 143. 




The otic ganglion, 
a small, reddish-gray 
body, is situated upon 
the inferior maxillary 
nerve, near its emer- 
gence from the fora- 
men ovale. 

6th. Motor Extern- 
us. — Passing through 
the cavernous sinus, 
it escapes from the cra- 
nium through the 
sphenoidal foramen or 
fissure, and is distri- 
buted to the external 
rectus muscle of the 
eyeball. Its paralysis 
will produce an in- 
ternal squint. A 
branch enters the ca- 
rotid canal to join 
the ganglion of Lau- 
monier. 



CRANIAL NERVES. 



173 



Fig. 144. 



7th. Facial and auditory. — Both branches enter into the internal 
meatus ; the auditory is also called portio mollis, and is distributed 
to the internal ear. The facial, also called portio dura, passes 
through the aqueduct of Fallopius, where it is formed by the super- 
ficial petrous, and emerges from the temporal bone at the stylo- 
mastoid foramen. 1 (Fig. 143.) 

Before it enters the parotid gland, it gives off the posterior auricu- 
lar, digastric, and stylo-hyoid branches. 
As it passes through the gland a plexus 
is formed, called the pes anserinus, from 
which proceed two principal branches, 
viz., the temporo-facial and cervico- 
facial. The temporo-facial is distributed 
by temporal, buccal, and malar branches, 
to muscles of the face; the cervico-facial 
is distributed by branches to the muscles 
upon the lower jaw and neck, which 
communicate with the cervical nerves. 

The 8th consists of three branches, the 
glossopharyngeal, the pneumo-gastric, 
and the spinal accessory, all of which 
emerge from the cranium at the posterior 
foramen lacerum or jugular foramen. 
(Fig. 144.) 

The glosso-pTiaryngeal is the highest 
branch of this pair. It passes out of the 
cranium by a distinct fibrous canal in the 
foramen, and descends between the in- 
ternal jugular vein and the carotid artery 
in curved line, adhering to the stylo- 
pharyngeus muscle. It is inferior to, 
and deeper in the neck than the gustatory 
nerve. Upon it are two ganglions — one 
is in the jugular foramen, and involves 
only a part of the nerve ; and the other 
is the petrous or Anderschian ganglion. 7 
From it arises numerous branches, which 
communicate with the facial, the sym- 
pathetic, and the pneumo-gastric, and 
also the filament called Jacobson's nerve. 
This nerve enters the tympanum through 
a small opening between the jugular and 
carotid foramina, to form the plexus upon 
the inner wall of the tympanum, in which 
the 5th pair and the sympathetic com- 
municate. 

15* 




174 SPINAL NERVES. 

From the gloeso-pharyngeal are given off branches, which with 
others from the sympathetic and pnenmogastric form the pharyn- 
geal plexus. 1 * It supplies the papillae at the posterior part of the 
tongue and the mucous membrane of the pharynx, and also some of 
the muscles of the tongue and pharynx. 

The pnenmogastric having escaped from the cranium by the pos- 
terior foramen lacerum, or jugular foramen, presents a ganglionic 
^i.:.r^iiiri.: :: i-illrl ilrxns ^:.ziglif i-rzziis. A sir. ill r:.rAi:r :; is ilsj 
found upon that portion which passes through the foramen. It then 
descends within the sheath of the vessels of the neck, lying behind 
and between the artery and vein, and entering the thorax and abdo- 
men, supplies the lungs and stomach, giving off the following 
branches : the superior pharyngeal** which assists in forming the 
pharyngeal plexus,** assisted by branches from the glosso-pharyngeal," 
the superior laryngeal, and sympathetic. This plexus is distributed 
to the muscles and mucous membrane of the pharynx. 

The superior laryngeal 15 arises from the ganglionic plexus, enters 
the larynx, and is distributed to its mucous membrane. The cardiac 
branches 16 are two or three in number, and descend to join the 
cardiac plexus. The inferior laryngeal* 1 or recurrent laryngeal, 
curves around the aorta upon the left side, and the subclavian upon 
the right ; ascending between the trachea and the oesophagus, it is 
distributed to the muscles of the larynx, communicating with the 
superior laryngeal and the sympathetic nerve. Anterior and pos- 
terior 13 19 pulmonary branches are given off in the thorax to form 
the pulmonary plexus. The oesophageal branches** surround the 
oesophagus, and with it enter the abdomen through the diaphragm, 
there to be spent upon the stomach and neighbouring viscera, and 
also communicate with the solar plexus. 

Spinal accessory. — This branch 9 of the eighth pair escapes also at 
the jugular foramen, and divides into two branches, one of which 
gives filaments to the superior pharyngeal nerve ; the other, which 
is the larger, descends obliquely backwards, and piercing the sterno- 
mastoid muscle, is distributed to the trapezius, after having commu- 
nicated with the upper cervical nerves. 21 ** 

9th. The Hypoglossal nerve emerges from the cranium through 
the anterior condyloid foramen; it then passes between the internal 
carotid artery and internal jugular vein, and curving around the 
occipital artery, sends branches to the muscles of the tongue. A 
branch, descendens noni, descends as a long, thin filament, in front 
of the sheath of the vessels, and below the middle of the neck ; 
forming a loop with a branch from the second and third cervical 
nerves. It communicates with the pnenmogastric and sympathetic. 

'SPINAL NERVES. 

There are thirty pairs of spinal nerves, each arising by two roots. 
After the union of the anterior or motor root with the posterior 



CERVICAL NERVES. 



175 



or sensitive root in the intervertebral foramen, the spinal nerves di- 
vide into two trunks, the posterior of which are much the smaller, 
and supply the muscles of the back; the anterior are large, and 
communicating with the ganglions of the sympathetic nerve, form 
plexuses which give off the principal nerves to the muscles of the 
trunk and extremities. 



CERVICAL NERVES. 



These are eight in number: the first is called the sub-occipital; 
it passes out of the spinal canal between the occiput and atlas, in a 
groove beneath the vertebral artery. It supplies the recti muscles, 
and unites with the first cervical so as to form a loop around the 
transverse process of the atlas. (Fig. 143.) 

Three superior cervical nerves anastomose freely and form a cer- 
vical plexus, which sends numerous branches to the muscles and skin 
of the neck, forming communications with the ninth and facial nerves. 
The principal branches from this plexus are the superficial, 10 t3 l6 
the great auricular, 12 the occipital, 16 and the supra-clavicular. The 
phrenic nerve 16 (Fig. 145), is formed by filaments from the second 
and third cervical nerves, and 



passing over the scalenus an- 
ticus muscle, and through 
the anterior mediastinum, ad- 
heres to the pericardium. It 
is distributed to the dia- 
phragm by several branches. 
The right passes in front of 
the innominata, the left 
passes in front of the aorta, 
and is more deeply situated 
than the right in the thorax. 

The four inferior cervical 
nerves, together with tne first 
dorsal, emerging from the 
spinal canal between the sca- 
lenus anticus and medius 
muscles, form a large plexus, 
by their anterior branches, 
which is plaited around the 
subclavian and axillary ar- 
teries. 

The brachial plexus gives 
off the following branches: 
the supra-scapular branch, 
which ascends upon the shoul- 
der and supplies its muscles ; 
passing through the coracoid 
notch. 



Fig. 145. 




176 LUMBAR NERVES. 

The Posterior or long thoracic branch is distributed to the serratus 
amicus muscle. (External r — pi:..: ry nerve of Bell.) 

The sub-scapular branches are two in number, and supply the 
sub-scapular muscle. 

The anterior or short thoracic are two in number, and supply the 
pectoral muscles. 

The lesser internal cutaneous, or nerve of Wrisberg, is distril; .:: : 1 
to the skin of the upper and posterior part of the arm. It is fre- 
quently joined by the first intercosto-humeral nerve. 

The circumflex or axillary nerve winds round the head of the 
humerus, in company with the posterior circumflex artery, and is 
distributed to the deltoid muscle. The internal cutaneous is a very 
small, thin filament passing down the inside of the arm. and sends 
branches across the superficial veins at the elbow, then is distri- 
buted to the skin, fascia, and fore-arm. The external or musculo- 
cutaneous* perforates the coraco-brachialis, and is also distributed 
to the muscles in front of the arm and integument of the fore-arm. 

The ulnar, 3 descending the arm, passes superficially under the 
internal condyle, and is finally distributed to the little finger, and 
the ulnar side of the ring finger. 

The radial or musculo-spiral is the largest of these nerves which 
come from the brachial plexus; it winds around the humerus, 
between the head of the triceps muscle, which it supplies with 
branches, and then descends the fore-arm supplying its muscles; a 
large branch accompanies the radial artery, supplying the wrist 
and thumb. 

The median 2 descends the arm in close company with the brachial 
artery, until it reaches the elbow ; it there passes between the two 
heads of the pronator teres muscle, and descending the fore-arm, 
between the flexor sublimis and profundus muscles, it is distributed 
to the fingers, with the exception of those supplied by the ulnar. 

DOE SAL NEBVES. , 

These are twelve in number ; the anterior branches are the larger, 
and are received into the intercostal grooves, in which they run, to 
be distributed to the muscles of the chest. 

The first dorsal nerve joins the brachial plexus. The intercosto- 
humeral nerves 5 are two in number; they proceed from the s: 
and third dorsal nerves, and perforate the second and third inter- 
costal spaces, to be distributed upon the skin of the arm ; the first 
frequently joins the nerve of "Wrisberg. 

IUMBAE XIETES. 

These are five in number ; the anterior branches of the four su- 
perior descending form the lumbar plexus, which is situated behind 
the psoas magnus muscle ; it is frequently connected with the last 
dorsal nerve. 



SACRAL NERVES. 



177 



The abdomino-cruraP branches are two or three in number, and 
pass obliquely over the quadratus lumborum muscle, and supply the 
muscles of the abdomen and the skin of the groin and genitals. 

The external eutaneous* crosses obliquely the iliacus internus 
muscle, tawards the anterior superior spinous process. It perforates 
the fascia lata, and is distributed to the integument of the thigh. 

The external spermatic* or genito-crural perforates the psoas 
muscle, and descending to the groin, supplies the cremaster muscle 
and skin of the thigh. 

The anterior crural 8 is the largest branch of the lumbar plexus. 
It emerges from under the psoas magnus muscle and passes 
under Poupart's ligament. It gives off the anterior, middle, and 
internal cutaneous branches, 66 7 which are distributed to the integu- 
ments; the long, or inter- 
nal, or long saphenous Fig- 146. 
nerve, accompanies the 
femoral artery as far as 
its perforation of the ad- 
ductor tendon, and then 
accompanies the saphena 
vein to the foot. 

The obturator accompa- 
nies the obturator artery, 
and emerges from the pel- 
vis at the upper portion of 
the thyroid foramen. It 
is distributed upon the 
obturator and adductor 
muscles. 



SACRAL NE R. V E S. 

These are five and 
sometimes six in number; 
the anterior trunks of the 
four upper, with a por- 
tion of the last dorsal, 
constitute the sacral 
plexus. The fifth and 
sixth are distributed to 

the gluteus maximus muscle, and to the skin. The sacral plexus is tri- 
angular in its shape, and situated upon the pyriformis muscle. From 
it are derived a few small branches sent to the muscles and viscera 
of the pelvis, and also the following nerves to the lower extremity. 

The gluteal^ which, emerging from the sacro-sciatic notch, divides 
into two large branches to supply the glutei muscles. (Fig. 147.) 

The pudicf or superior long pudendal, accompanies the internal 
pudic artery, and supplies the perineum, and organs of generation ; 




178 



SACRAL NERVES. 



Fig. 



;, - 



it divides into two branches, the superior 
continuing to the extremity of the penis 
with the dorsal artery. 

The lesser ischiatic 3 escapes from the pelvis 
between the pyriformis muscle and the.great 
sacro-sciatic ligament, and divides into the 
inferior long pudendal or perineal, 5 which 
winds around the tuberosity of the ischium, 
and is distributed to the integuments of the 
perineum ; and the posterior cutaneous , 6 a 
long filament passing down the back of the 
thigh and leg, to be spent upon the integu- 
ments. 

The great sciatic'' is the largest nerve in 
the body; it escapes from the pelvis beneath 
the pyriformis muscle, and descends the 
back of the thigh between the flexor muscles ; 
about one-third above the knee, it divides 
into two large branches, called peroneal and 
popliteal. 

The popiteal 3 descends through the pop- 
liteal space, giving off numerous muscular 
and cutaneous branches, one of which is the 
external or short saphenous nerve,™ is joined 
by the internal peroneo-cutaneous nerve, 11 
and becomes superficial near the ankle ; it 
then passes behind the external malleolus, 
and supplies the skin, external malleolus; 
and the foot. 

The posterior tibial 9 is a corftinua,tion of 
the popliteal, descending the back of the leg 
in company with the posterior tibial artery ; 
it is finally distributed upon the sole of the 
foot by two branches called the external and 
internal plantar nerves. 

The internal plantar is the larger, and is 
distributed to the first, second, and third 
toes, and to the inner side of the fourth. 

The external plantar is distributed to the 
little toe, and the outer side of the next toe. 

The plantar nerves are distributed to the 
toes upon the same plan as the median and 
ulnar nerves are to the fingers. 

The peroneal nerve extends towards the 
head of the fibula, passing between the ex- 
ternal side of the tendon of the biceps and 
the outer part of the external head of the 
gastrocnemius. It gives off the following 



SYMPATHETIC NERVE. 



179 



cutaneous "branches, and then divides into the external peroneal and 
anterior tibial. The internal peroneo-cutaneous is the largest cutaneous 
branch; it joins with the external saphenous or communicans tzbise. 

The external peroneo-cutaneous is distributed to the skin along 
the fibula? 

The external peroneal passes down upon the fibular side of the 
leg, through the peroneus longus muscle, and becoming superficial 
in the lower third of the leg, perforates the crural fascia, and is 
distributed to the integuments of the foot and ankle. 

The anterior tibial descends in front of the interosseous ligament, 
in company with the anterior tibial artery, and is distributed to the 
muscles of the leg, and to the muscles and skin upon the foot. 

SYMPATHETIC NERVE. 

The sympathetic system consists of two chains of ganglia, united 
to each other and to the cranial and spinal nerves. Each ganglion 
may be considered as a distinct nervous centre, and is placed oppo- 
site the intervertebral space. The two sides of the sympathetic sys- 
tem are united in the head by the ganglion of Ribes, which may be con- 
sidered as the origin of the sympathetic nerve. There is also a 
ganglion in the median line of the coccyx, whereby the two lateral 
halves of the sympathetic are united below. 

It is distributed in connexion with all the other nerves of the 
body, and by means of plexuses supplies all the internal organs ; 
these plexuses take the name of the artery with which they are 
connected, or of the organ to which they are distributed. 

Fig. 148. 







180 CERVICAL GANGLIA. 

The cranial ganglia of the sympathetic are five in number, viz. : 
ganglion of Riles, 1 which is small, and situated upon the anterior 
communicating artery; a filament of it 2 joins the sixth nerve, 8 
which communicates with the carotid plexus. 3 The carotid plexus 
surrounds the carotid artery in the carotid canal, and frequently 
contains a ganglion called after Laumonier. This plexus is joined 
by the deep petrous branch of the vidian nerve, and was formerly 
considered the origin of the sympathetic. 

-The lenticular ganglion 4 is small and flattened, reposing between 
the optic nerve and the external rectus muscle. This ganglion 
communicates with a branch of the nasal nerve, 6 and a branch of 
the third, called ciliary 5 ; a small filament 7 passes from this ganglion 
to join the carotid plexus. 

The sphenopalatine ganglion is called also Meckel's ganglion. 9 
From this are given off the vidian nerve," the deep petrous branch 
of which joins the carotid plexus, as has been mentioned, and the 
superficial petrous, 16 which enters the hiatus Fallopii, and emerging 
at the G-laserian fissure as the chorda tympani, l2 descends in con- 
nexion with the gustatory nerve 19 to join the submaxillary ganglion. 

The ganglion of Meckel communicates with the superior maxil- 
lary nerve by means of its two ascending branches, called pterygo- 
palatine. 10 One of its spheno-palatine branches, 12 called naso-pala- 
tine, 13 joins its fellow in the foramen incisivum,to form the ganglion 
of Cloquet,* or naso-palatine ganglion. Its descending branches 11 
supply the palate, gums, and fauces. 

The otic ganglion (Arnold's), is a small oval ganglion, adhering to 
the inner surface of the inferior maxillary nerve, below the foramen 
ovale ; it sends branches of communication to the superior and infe- 
rior maxillary, to the vidian and tympanic nerves, and it also sup- 
plies the tensor tympani and the tensor palati muscles. 

CEETICAL GANGLIA. 

These are three in number. The first 1 is a long, gray, spindle- 
shaped ganglion, extending to the lower border of the third cervical 
vertebra, behind the sheath of the vessels of the neck. Its branches 
are numerous, and some are very soft, hence termed nervi moV.es. 
They communicate with the anterior trunks 4 of the first, second, 
and third cervical nerves ; and by an ascending branch 2 with the 
carotid plexus, and by a descending branch 3 with the second cervical 
ganglion. Its internal branches 5 join the facial, eighth, and ninth 
nerves, and the pharyngeal plexus. A number of branches join to 
form the superior cardiac nerve, 6 which descends behind the vessels 
and joins the cardiac plexus. 

The middle cervical ganglion is usually small, and sometimes 
wanting. It rests upon the inferior thyroid artery in front of the 
fifth or sixth cervical vertebra. It is often called the thyroid gan- 
glion. Its branches join the superior and inferior cervlica ganglia, 



THORACIC GANGLIA. 



181 



and the anterior trunks of the third, fourth, and fifth cervical nerves ; 
it also sends the middle cardiac nerve 1 to join the cardiac plexus. 

The inferior cervical ganglion is larger than the last, and is 
situated in front- of the root of the transverse process of the seventh 
cervical vertebra. Its filaments join the sixth, seventh, and eighth 
cervical nerves, and also form the inferior cardiac nerve, which joins 
the middle cardiac nerve and the cardiac plexus. 

The cardiac plexus is situated behind the arch of the aorta, upon 
the bifurcation of the trachea. Its branches, in conjunction with 
the par vagum and descendens noni, form the anterior and posterior 
cardiac plexuses; from these plexuses are derived the filaments 
which supply the heart. 



THORACIC GANGLIA. 

These are twelve in number, situated 
at the intervertebral spaces. They are 
small and connected with each other as well 
as with the anterior trunks of the spinal 
nerves. The great splanchnic* is formed 
by filaments from the sixth to the tenth 
ganglion j it descends in the posterior medi- 
astinum, and pierces the diaphragm at or 
near the foramen aorticum, to form the 
semilunar ganglion. The lesser splanchnic 
nerve xi is formed by filaments from the tenth 
and eleventh ganglia ; it pierces the dia- 
phragm and joins the semilunar ganglion 
and the renal plexus. 

The semilunar ganglion 1 * consists of a 
number of smaller ganglia formed upon fila- 
ments of the splanchnic nerve after it has 
entered the abdomen ; they are arranged 
in a crescentic manner, 13 and situated upon 
the aorta and coeliac axis. 

The solar plexus is a network on the 
sides of the aorta, and extends as far as the 
renal arteries. It is a number of filaments 
connecting the portions of the semilunar 
ganglia ; and from it proceed smaller plex- 
uses, which accompany the large arterial 
trunks; thus, the hepatic plexus is the 
network which surrounds the hepatic ar- 
tery, and is distributed to the liver, gall- 
bladder, &c. The splenic plexus accom- 
panies the splenic artery and supplies the 
spleen ; thus also, are distributed, the renal, 
mesenteric, and other plexuses. 

16 



Fig. 149. 




ORGANS OF SENSE. — NOSE. 



A >" D 5 A C B A L GANGLIA. 



The janglia are four or five in number, which are mri : 1 

with each other and the spinal nerves. They form a plexus npon 
the aorta, which receives filaments from the solar and hypogastric 
plexuses. 

The hypogastric plexus 16 is formed by branches of the lumbar 15 
and aortic plexuses and filaments from the sac jlia. From 

it are supplied all the viscera of the pelvis. The sacral ganglia are 
three or four in number. Mie last is called impar" 8 or azygos, being 
situated in the median line of the coccyx, and constituting the r 

ting ganglion of the sympathetic. 



ECTIOX VII. 



ORGANS OP SENSE. 



NOSE. 



Kg. 150. 



The nose consists of two portions, an external projection upon the 
fa :e. and an internal cavity. Th : portion is formed by the 

nasal processes of the superior maxillary bones, the nas^l bones, 
and by five cartilages, two of which are placed upon either side 
and one in the middle. Th& ci s septum is placed in the 

median line ; 2 it is thick, flat, and triangular, uniting by its sur eric r 
e ige with the ethmoid, and by its inferior edsre 
— ith the vomer. Its anterior edge unites with 
:_r and cartilages. It frequently 

deviates from the median line. The lateral 
cartilages 3 are triangular, one being placed on 
either side, attached above and behind to the 
bone, in front with the septum, and below with 
the alar cartilage. The alar cartilages* are two 
in number ; they form the lower portion of the 
_ r. and the opening called the nostril. It is 
an irregular, semi-elliptical cartilage, and has 
a number of small pie : I : artilage attached 
to it, by which the nostril is kept open. 
cartilages are held together by a fibrous tissue. 
The skin which covers the nose is thick and 
strong, and covered with numerous sebaceous 
follicles, which are frequently recognised by 
their being discoloured. The hairs visible in the nostril are termed 

'SSOR. 




THE EYE AND ITS APPENDAGES. 183 

The cavity of the nose is formed by the nasal fossse. The roof 
is the cribriform plate of the ethmoid, the floor is the hard palate. 
Upon each side there are three scrolls formed by the turbinate 
bones. Between the superior and middle turbinate bones is the 
superior meatus; between the middle and inferior turbinate bones 
is the middle meatus ; between the inferior turbinate bone and the 
floor of the nose is the inferior meatus. It is lined by a mucous 
membrane called pituitary, or Schneider ian, which is thick, soft, 
and red, owing to its vascularity, and largely supplied with nerves, 
being the seat of smell. It lines the meatuses of the nose, and is 
continuous with the mucous membrane of the mouth, lachrymal 
canal, Eustachian tube, frontal sinus, and ethmoidal cells. It is 
supplied by the first and fifth pairs of nerves. 

THE EYE AND ITS APPENDAGES. 

The eyeball is a sphere, of about one inch in diameter, antero- 
posterior^, and somewhat less transversely. It is surrounded by a 
fibrous capsule, which is continuous with the sheath of the optic 
nerve behind, and the cartilages of the eyelids in front. All the 
muscles of the ball of the eye lie behind this capsule or fascia, and 
perforate it," in order to be inserted into the sclerotic coat. 

The sclerotic coat 1 is a dense, fibrous, white membrane, thinner in 
front, where it receives the cornea, than it is behind, where it is 
perforated by the optic nerve. The circular edge in contact with 
the cornea is bevelled. The external surface is anteriorly covered 
by the conjunctiva, and posteriorly by fat. Its internal surface is 
connected with the choroid coat. It is perforated by numerous 
small foramina transmitting arteries and nerves. 

The cornea 11 fills up the opening in the anterior part of the sclero- 
tica, and forms about one-sixth of the whole eyeball j it is more 
convex than the sclerotica, and therefore forms a projection in front. 

Fig. 151. 




1*4 the ete Am rrs ansKDASES. 

It is transparent and apparently homogeneous, but is in : com- 
posed of numerous lamina, between which there is a slight quantity 
of fluid- It is covered anteriorly by the : m fun ::: va t^and] 

;t :i: - ~ ;: :_: r a:.~ie:~as zzziiii 

The cental of Fontanel is a veno~s anus, niir the border of the 



The choroid coaf* is a thin, Tascular tunic of the same extent 
the sclerotica, with which ft is in contact externally. It is filled 
with a black colouring matter called jrigmentmm nigrum, and con- 
sists principally of arteries and! veins. It h - rveral 
nerves. Its internal layer is composed priz - :: : — . and 
called memhrana Rwysekiana ; externally it is composed principally 
of reins, called rasa rorticosa. 

The ciliary ligament^ is a f : i .; - ielicate ring, at the jut etion 
:: :_r vrtea ".ii e:ier::::a. —'zii'z. tz::es :lie ;x:er~il e::Irr :: 
:le iris ml im "iliary "mm. 

The ciliary lnoehf is formed by the mm: portion : the :- 
raid coat, in contact with the ciliary ligam -. i a :. b if 
seventy or eighty short folds, called ciliary processes; which con- 
verge and are smaller behind than they are in front ; they surround 

I'm: ~ ?■:%- is a small, pay 5 behind the :il:ary 

Immmm : : 1 i Mmriim :im mmim :: :i: 
z-z '-''-'- ciliary processes. Its contraction pre 

the lens* towards die cornea.* 

The iris (fig. 151 : mm. areolar 
membrane, 6 consisting of contractile tissue, 
r and forming a vertical septum between the 
anterior and posterior eham 
Z- h 1 rforated nearly in the centre by a 
foramen called the pmpilj which in : 
lire is :imemm :m : _ "■'.,. 

Its external border is attache 1 to tin : iliary 
ligament. The anterior surfc.:: r 
:: i mmsi :: :r:~ - .mm. smmlel ml 
striated; towards' the pupil the colour is 
deeper. Its posterior surface (sometimes called the 1 . vtsred 

with a thick layer of pigmentum nigrum, and is in contact with the 
ciliary processes. It may contain a few muscular fm baits structure. 
Z • supplied by the ciliary arteries, branches of the ophthalmic, 
and by the ciliary nerves, which pass from the lenticular ganglion 
:::::: :m imriii :m: :: *:e Imrimml mm it. 

The retina, 9 is a soft, white membrane, within the choroid coat, 
and is considered by some to be an expansion of the optic nerve. 
and by others as a distinct nervous structure in connexion with the 
optic nerve. Internally it is in contact with the vitreous humour. 




THE EYE AND ITS APPENDAGES. 185 

It commences at the optic nerve, and terminates anteriorly by a 
jagged edge, called or a serrata, behind the ciliary body. It is 
thicker behind than it is in front. When perfectly fresh it has a pink- 
ish tint, and is" semi-transparent. Its inner surface is of a fibrous 
character, consisting of radiating tubular fibres of the optic nerve. 
Its external surface consists of a finely-granulated matrix, inter- 
spersed with very delicate vessels. The optic nerve, 15 enters the 
globe of the eye on the inner side of its axis, and the point where 
it is connected with the retina is incapable of vision. Directly in 
the axis there exists upon the retina the yellow spot of Soemmering, 
a slight elevation with a minute perforation in its summit. The 
central artery of the retina enters through the optic nerve, and tra- 
versing the vitreous humour, supplies the retina and lens. 

Membrana Jacobi. — Is a thin lamina, existing between the cho- 
roid and the retina, consisting of a number of club-shaped rods, 
interspersed with transparent cells. 

The vitreous humour 13 has a transparent, jelly-like appearance, 
and is of a globular form. It consists of a viscous fluid, held in 
cells formed from the hyaloid membrane, which surrounds it. It. is 
colourless, and its structure is best exhibited by freezing. 

The canal of Petit, 9 is formed between the laminae of the hyaloid 
membrane, and surrounds the edge of the lens. 

The zone of Zinn, is a circle of plaitings upon the vitreous hu- 
mour, which dove-tail with the ciliary processes. 

The Crystalline lens 12 is a double convex lens, whose posterior 
surface is more convex than its anterior. In childhood it is spheri- 
cal, and in old age it is flattened. It is transparent and soft, and 
surrounded by a capsule which contains a thin fluid, called liquor 
Morgagni. It consists of concentric laminas, having a tendency to 
divide into three equal segments. 

The aqueous humour 10 is a transparent fluid, occupying the ante- 
rior and posterior chambers of the eye, bathing the posterior surface 
of the cornea, and the anterior surface of the capsule of the lens. 
It is from four to five grains in quantity. This is said to be secreted 
by the membrane of Demours, which lines the whole of the anterior 
and posterior chambers. This membrane can only be traced upon 
the posterior surface of the cornea. 

The eyebroios are two elevations of the skin covered with short, 
stiff hairs, protecting the eye from too strong a light, and from the 
perspiration flowing down the forehead ; they materially affect the 
expression of countenance. The space between, the two is called 
glabella. 

The eyelids or palpebral, consist of skin, muscular fibres, cartilage, 
and mucous membrane ; and when in contact, leave a triangular 
canal, which passes transversely between them. Their edges are 

16* 



186 



THE EYE AND ITS APPENDAGES. 




covered with cilia, or eyelashes, which are short, stiff, curved hairs, 
protecting the eyeball. 

Tarsal cartilages. — Are two in number. That of the upper lid 

is larger than that of the 
Fig. 153. lower ; they are crescen- 

tic in shape, and attached 
by the external and in- 
ternal palpebral liga- 
ments. 

Conjunctiva. — Is a soft 
mucous membrane lining 
the lids, and covering the 
anterior surface of the 
ball, forming a fold called 
'plica semilunaris, near 
the inner canthus. It is 
vascular, and well sup- 
plied with nerves. 

Meibomian glands. — 

Are twenty or thirty 

small yellow thread-like 

glands between the conjunctiva and the posterior surface of the lids, 

discharging by numerous orifices along the edges of the lids a viscid 

fluid which prevents the overflow of tears at night. 

Caruncula lachrymalis. 7 — A small, red elevation, in the internal 
can thus, about the size of a grain of wheat ', consisting of an aggre- 
gation of small sebaceous glands, and often furnished with hairs. 

Lachrymal gland? — A lobulated gland, about the size of a filbert, 
and of a light pink colour, situated in a fossa on the roof of the 
orbit, near the external angular process. It consists of two portions, 
viz., orbital and palpebral. It discharges tears by ten or twelve 
ducts, 4 whose orifices open upon the upper and outer part of the 
conjunctiva. 

Lachrymal canals. — These open by two small orifices upon a 
papilla at the inner part of each lid, called puncta lachrymalia. 6 

The tears enter these orifices 
and are conveyed along a bent 
canal into the lachrymal sac. 

Tensor tarsi or Horner's 
muscle. — (Fig. 154.) — Arises 
from the os unguis, 4 and is in- 
serted by two divisions 5 into 
the orifices of the lachrymal 
canal. Its nasal face adheres 
to the lachrymal sac. 

Lachrymal sac and nasal 
duct. — Is a continuous tube 





THE EAR. 187 

contained in the passage formed by the nasal process of the superior 
maxillary, the tmguiform, and inferior turbinated bones. Its external 
coat is fibrous, and its internal mucous ; it is larger above than it is 
below, and opens into the inferior meatus of the nose. The mucous 
lining forms a semicircular fold or valve. 

The muscles : Levator palpebral superioris.* — Origin, near the 
optic foramen. Insertion, by a broad aponeurosis into the upper 
lid. It draws the lid upwards. 

The four straight muscles, arise around the optic foramen ; and 
are inserted, by tendinous ex- 
pansions, within a few lines ■ Fi S- 155 - 
of the cornea. They are 
called superior, 9 inferior, 13 in- 
ternal, 10 and external. 11 

The superior oblique mus- 
cle, 5 arises from the edge of 
the optic foramen, and plays 
over a tendinous pulley 6 upon 
the orbitary ridge of the fron- 
tal bone ; is inserted into the 
sclerotica beneath, and beyond the superior rectus. 

The inferior oblique, 8 arises from the nasal process of the supe- 
rior maxillary bone ; and passing below the inferior rectus, is in- 
serted beyond it, into the sclerotica. 

THE EAR. 

The organ of hearing is composed of three parts : the External 
Ear, the Middle Ear, or tympanum, and the Internal Ear, or laby- 
rinth. 

The external ear consists of two parts, the pinna, which is 
moveable upon the side of the head, and the meatus, a tube leading 
from it. 

The pinna has a number of ridges and hollows upon its surface ; 
these are : a prominent rim or helix ; and within it another curved 
prominence, the antihelix, which bifurcates above, so as to enclose a 
space, called the scaphoid fossa, and surround a deep, capacious, 
central cup, the concha. The space between the helix and antihe- 
lix is the fossa innominata. At the end of the helix, in front of 
the* concha, is a small detached eminence, the tragus, so named 
from its bearing a tuft of hair, resembling a goat's beard. Opposite 
this, behind and below the concha, is the antitragus. Below is the 
pendulous lobe, composed of dense areolar and adipose tissues. The 
concha is imperfectly divided into an upper and lower part, by the 
anterior curved extremity of the helix. 

The shin of the pinna is thin, and contains an abundance of seba- 
ceous follicles. 



188 



THE EAR. 



The fibro-cartilage is an oval, elastic plate, of a yellowish colour, 
in which are several fissures filled up with fibrous tissue. It is 
attached by an anterior ligament, which is triangular, broad, and 
strong, to the zygomatic process, and by the posterior ligament to 
the mastoid process. 



Fig. 156, 




The muscles which move the pinna as a whole are the attollens 
auriculse, arising from the aponeurosis of the occipito-frontalis ; and 
inserted into the outer side of the cartilage of the ear opposite the 
scaphoid fossa : the attrahens auriculse, arising also from the same 
aponeurosis in front of the zygoma, and inserted into the forepart 
of the helix ; and the retraliens auriculae, arising from the mastoid 
process of the temporal bone, and inserted into the back part of 
the concha. There are also some small muscles upon the pinna 
itself. The major helicis is narrow, about half an inch long, thin, 
and situated at the arched superior and anterior part of the helix ; 
its fibres are vertical. The minor helicis is very small, and situ- 
ated at the inferior and posterior arch of the helix. The tragicus 
is three-cornered, tolerably thick, with vertical fibres upon the 
tragus. The antitragicus is narrow and short, and passes from the 
antitragicus to the antihelix. The transversus auriculse is on the 
posterior surface of the ear, extending from the convexity of the 
concha to the external part of the antihelix. The dilatator conchse 
extends from the meatus auditorius to the anterior part of the 
tragus, which it draws forwards, and thus dilates the concha. The 



THE EAR. 



189 



obliquus auriculce is upon the internal surface of the ear, between 
the elevations of the fossa innominata and the concha. 

The meatus* is a cartilaginous and bony canal, of about one inch 
in length, narrow in the middle, and curved downwards ; the skin 
lining it^is covered with hairs, and glands secreting wax. 

Fig. 157. 




Membrana tympani. — The drum of the ear is a thin, semi-trans- 
parent, oval membrane, separating the cavity of the tympanum 
from the external ear. Its internal surface is slightly convex, and 
attached to the handle of the malleus. It is directed obliquely 
downwards and inwards, and it consists of three laminae, the middle 
of which is strong and fibrous, and attached to the rim of the bone. 
The external surface is a continuation of the cuticle, and the in- 
ternal of the mucous membrane, lining the cavity. 

The middle ear or tympanum* is a small, irregular, bony cavity, 
in the petrous portion of the temporal bone, and bounded in front 
by the membrana tympani. It is filled with air, which enters by 
the Eustachian tube ; c and contains a chain of small bones, and 
openings into the mastoid cells. 

The internal wall of the tympanum has two orifices of communi- 
cation with the internal ear in the dried bone ; the fenestra ovalis, a 
an oblong opening leading to the vestibule, and the fenestra ro- 
tunda* opening into the cochlea ; both of these are closed by mem- 
brane, which prevents the escape of fluid contained in these inner 
chambers, and communicates vibrations to it. The fenestra ovalis 
is also closed by the foot-piece of the stapes. Between the fenestra 



190 THE BAR. 

is the promontory, an elevation corresponding to the first turn of 
the cochlea, and furrowed with two or three grooves for the nerves 
which form the anastomosis of Jacobson. The pyramid* is a small 
conical projection behind the fenestra ovalis, presenting a small 
orifice at its summit, through which emerges the tendon of the 
stapedius muscle, which is contained within. At the base of the 
pyramid is an aperture through which the chorda tympani enters 
the tympanum ; thence this nerve passes forwards between the han- 
dle of the malleus and the long arm of the incus, and emerges 
through the Glaserian fissure. Above the pyramid an arched pro- 
minence e indicates the course of the aqueduct of Fallopius, close to 
the tympanum, and behind this is the free communication with the 
mastoid cells. At the upper part of the tympanum is the coch- 
leariform process, which bounds the canal of the tensor tympani 
muscle. Below this is the commencement of the Eustachian tube, 
which is a straight canal, about two inches long, at first bony, then 
cartilaginous, and opening by a trumpet-shaped orifice into the 
pharynx, behind the inferior turbinated bone. 

The Bones of the tympanum are four in number ) l the malleus, or 
hammer, has a head™ separated by a 
Fig. 158. neck from a handle , h which is imbed- 

ded in the drum of the ear. A slight 
projection from the neck, receives the 
insertion of the tensor tympani mus- 
cle. The processus gracilis is long and 
thin, and extends from the neck for- 
wards and outwards to enter the Grla- 
serian fissure; to it is attached the 
laxator tympani muscle. A short co- 
nical process projecting from the back 
of the head, articulates with the 
incus. 

The Incus, or anvil, resembles a 
molar tooth. Its body articulates with the malleus. Its short crus sc 
is -directed backwards, and projects towards the mastoid cells. Its 
long crus lc has a hooked apex, which is bent inwards, and in contact 
with a small lenticular bone, called orbiculare* which is often fused 
into the incus. 

The stapes or stirrup has its base or foot-piece s fitting the fenestra 
ovalis ; one of its sides is more curved than the other, and its head 
is in contact with the orbiculare. 

The muscles moving these bones are the tensor tympani, arising 
from the spinous process of the sphenoid bone and from the Eusta- 
chian tube, and passing through that canal above the Eustachian tube, 
to be inserted into the upper part of the handle of the malleus, which 
it draws inward, and thus stretches the membrane of the tympanum. 




THE EAR. 



191 



The laxator ti/mpani arises from the spinous process of the sphenoid 
bone, and passes through the Glaserian fissure, to be inserted into 
the processus gracilis of the malleus. There is sometimes another 
and lesser laxator tympani. The stapedius arises from the interior 
of the pyramid, and its tendon escapes from its summit, to be in- 
serted into the head of the stapes. 

Fig. 159. 




The Internal ear, or labyrinth, consists of a bony and mem- 
branous portion; the bony labyrinth consists of three parts, the 
vestibule (V), the semicircular canals (S), and the cochlea (C). 

The vestibule is a small, three-cornered cavity, behind the inter- 
nal wall of the tympanum; into it open the semicircular canals, 3 by 
five orifices behind, and the cochlea, by a single one in front. On 
its outer wall is the fenestra ovalis, and on its inner, several mi- 
nute holes, including the macula cribrosa, for the entrance of a por- 
tion of the auditory nerve. The aqueduct of the vestibule also 
penetrates it, from the posterior surface of the petrous bone. It 
also contains two depressions, called fossa hemispherica and fossa 
semi-elliptica.° 

The semicircular canals s are three curved cylinders of half a line 
in diameter, whose extremities open into the vestibule by five ori- 
fices, each extremity being expanded like a flask and called am- 
pulla. 3 ' Two of these canals s P are vertical, and one is horizontal. 
The cochlea resembles a snail-shell, and consists of a conical canal, 
which makes two turns a*nd a half spirally around an axis called the 



192 THE EAR. 

modiolus, which is a porous mass of bone, whose base is perforated 
by the filaments of the cochlear nerve. The tube of the cochlea is 
divided into two passages by the lamina spiralis, which terminates 
at the apex with a hook ? called hamulus; which is covered by the 
cupola. The upper passage of the canal is called scala vestibidi, 
and the lower is the scala t-ympani. These passages communicate 
by an opening at the apex called helkotrema. The scala vestibuli 
opens into the vestibule, and the scala tympani through the fenestra 
rotunda into the tympanum. The aqueduct of the cochlea opens by 
one extremity into the scala tympani, and by the other upon the 
inferior surface of the petrous portion of the temporal bone. 

The membranous labyrinth has the same shape as the bony 
cavities which it lines, and consists of a delicate membrane com- 
posed of several layers, containing the limpid fluid of Cotunnius, 
and the two small calcareous masses called otoconites. 

The endolymph is the fluid contained within the membranous la- 
byrinth ; the perilymph is the fluid contained between the bony and 
membranous labyrinths. 

The auditory nerve enters the meatus auditorius internus and 
divides into a vestibular and cochlear branch, which are expanded 
upon the membranous labyrinth and the walls of the cochlea. 



THE END. 



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